application of gelatin incorporated with red pitaya peel...

Research ArticleApplication of Gelatin Incorporated with Red Pitaya PeelMethanol Extract as Edible Coating for Quality Enhancement ofCrayfish (Procambarus clarkii) during Refrigerated Storage

Wenru Liu123 Yong Shen 123 Na Li123 Jun Mei 123 and Jing Xie 123

1Shanghai Engineering Research Center of Aquatic Product Processing amp PreservationShanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving EvaluationShanghai 201306 China2National Experimental Teaching Demonstration Center for Food Science and Engineering Shanghai Ocean UniversityShanghai 201306 China3College of Food Science and Technology Shanghai Ocean University Shanghai 201306 China

Correspondence should be addressed to Jun Mei delightmayhotmailcom and Jing Xie jxieshoueducn

Received 25 March 2019 Revised 16 June 2019 Accepted 7 July 2019 Published 2 September 2019

Guest Editor Karolina Krasniewska

Copyright copy 2019 Wenru Liu et al is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

China is one of the largest producers of red pitaya in the world and responsible for disposal of the huge amount of peel generatedas a waste e objective of this research was to evaluate the eect of the addition of red pitaya peel extract (RPPE 10 20 or30 (wv)) and 01 ε-polylysine (ε-PL) to a sh gelatin edible coating on the preservation of deshelled craysh (Procambarusclarkii) during refrigerated storage e physicochemical and water migration of the samples were determined during 8-daystorage Deshelled craysh packaged in edible coatings exhibited signicantly (plt 005) lower values for total volatile basicnitrogen (TVB-N) K value maintenance and free amino acids (FAAs) is study shows that application of an edible coatingincorporated with RPPE and ε-PL is an eective strategy in retarding the quality deterioration in deshelled craysh during storage

1 Introduction

Craysh (Procambarus clarkii) with high protein and lowfat is a freshwater economic shrimp in China [1] In 2016the total craysh output was about 90 million tons Crayshare usually shucked so that they can be sold as ready-maderaw meat which is more acceptable to consumers andmeets the needs of the freshwater product industry [2]However craysh are highly susceptible to microbial in-fection after shucking and they are not easy to preserve [3]Free amino acids and other soluble non-nitrogenoussubstances in craysh serve as digestible nutrients formicrobial growth [4] and this causes a loss in freshness andlowers the quality of the product causing a market loss ofcraysh erefore the development of storage methodsthat reduce or delay the loss of freshness is important to thecraysh industry

Pitaya belonging to Cactaceae family is a native fruitfrom Mexico and Central and South America [5 6] Redpitaya peel is considered a waste of the processing andrepresents 33 of the fruit total weight [7] Red pitaya peel(RPP) is abundant in antioxidant compounds and has animportant antioxidant potential [8] which could ensurethe chemical stability of deshelled craysh during re-frigerated storage Pitaya peel is a residue of fruit con-sumption and processing [9] In an era of great concernwith environmental problems food by-product valoriza-tion and application of green extraction processes havegained much attention [10] Extracting the active in-gredient from the peel can improve the utilization of thepeel Meanwhile peel extracts are commonly used as bi-ological preservatives in many food processes especially inthe aquatic product to prolong shelf life including essentialoils from tangerine peels and mango peel extracts and

HindawiJournal of Food QualityVolume 2019 Article ID 1715946 8 pageshttpsdoiorg10115520191715946

polyphenols from apple peels [6 11 12] Edible coating canbe used to protect phenolic compounds from oxidation byexternal factors such as the presence of light oxygen metalions pH and high temperatures [13] and provide freshfood protection to prevent quality loss and weight lossSeveral researchers have applied it to the storage of aquaticproducts [14ndash16]

In this study we investigated the effect of the additionand the level (10 20 and 30 (wv)) of red pitaya peelextract (RPPE) combined with 01 ε-PL on the physico-chemical and water migration of deshelled crayfish stored at4degC under aerobic condition

2 Materials and Methods

21 Preparation of RPPE Fresh red pitaya fruits were ob-tained from the producer in Zhanjiang China and the peelwas manually separated lyophilized for 48 h and milled in acommercial blender (WBL1022S Guangdong Midea Elec-tric Appliances Co Ltd China) 0e fine powder siftedthrough a 40-mesh sieve was collected and stored in anamber flask 0e powder (250 g) was mixed with 200mL ofmethanol and water (80 20 vv) solution and then trans-ferred to an ultrasonic extractor (KQ-100DE KunshanUltrasound Instrument Co Jiangsu China) at a power of240W for 30min After extraction the solution wascentrifuged at 3100 times g for 15min at 4degC and the super-natant was transferred to an amber flask 0e extract wasconcentrated using a rotary evaporator (RE-5299 ShanghaiYarong Biochemical Instrument Factory Shanghai China)at 50 rpm and 40degC under vacuum to remove methanol andthen freeze-dried 0e freeze-dried RPPE powder sampleswere stored at 4degC in the dark [8]

22 Determination of Polyphenols of RPPE

221 Total Polyphenolic Content 0e total polyphenoliccontent was determined by the FolinndashCiocalteu colorimetricmethod based on oxidationreduction reactions of phenolsand the results were expressed as milligram gallic acidequivalent per gram dry weight (mgmiddotGAEgmiddotdw) of RPPEpowder [17]

222 Determination of Betacyanin Content 0e absorbanceof betacyanin was determined using the method describedby de Mello et al [18] Quantification of betalains wascalculated by the following equation

betacyanin contentmg100 g

1113888 1113889 A times DF times MW times V times 100

ε times L times W

(1)

where A is the absorption value at 538 nm DF is the dilutionfactor MW is the molecular weight of betanin (550 gmol)V is the pigment solution volume (mL) ε is the molarextinction coefficients of betanin (60000 Lmiddotmolminus1middotcmminus1) L isthe path length of the cuvette and W is the weight ofpigment powder (g)

23 Extraction of Salmon Skin Gelatin 0is method de-scribed by Tkaczewska et al [19] was used with somemodifications 0e salmon skins were cut into small pieces(5times 5 cm) and poured into water to remove adhesive im-purities and soaked in 005molmiddotLminus1 sodium hydroxide for2 h at a samplealkali solution ratio of 1 6 (wv) 0en skinswere washedwith distilled water at 4degC until neutral to removethe remaining alkali soaked in 005molmiddotLminus1 acetic acid for 2 hat a sampleacid solution ratio of 1 6 (wv) and then alsowashed to neutrality at 4degC 0e pretreated skins wereextracted with distilled water at 50degC for 6 h and the mixturewas filtered and then lyophilized to obtain the gelatin sample

24 Preparation of Preservative Solutions Gelatin solution(12 (wv)) was prepared by dispersing gelatin in distilledwater at 60degC and stirring for 3h After dissolved completelythe solution was filtered with cheesecloth and then 01 ε-PLwas added and the mixture was homogenized at 30k rpm for60 s All the edible coating solutions (G gelatin solutioncontaining 01 (wv) ε-PL G-1 RPPE gelatin solutioncontaining 01 (wv) ε-PL and 1 RPPE G-2 RPPE gelatinsolution containing 01 (wv) ε-PL and 2 RPPE G-3RPPE gelatin solution containing 01 (wv) ε-PL and 3RPPE)were prepared and adjusted to pH70 Finally a vacuumpump was applied to remove air bubbles from the solutions

25 Determination of Antioxidant Activity of PreservativeSolutions 0e antiradical activities of preservative solutionswere determined using the stable radical DPPH (22diphenyl-1-picrylhydrazyl) according to Mansour et al [20]0e ABTS (22prime-azino-bis(3-ethylbenzothiazoline-6-sul-phonic acid)) radical-scavenging activity was conductedusing the method described by Zhou et al [21] 0e anti-oxidant capacity of the sample was expressed in terms of themolar concentration of the standard

26 Preparation and Treatment of Crayfish Samples Freshred swamp crayfish (Procambarus clarkii) in the same size(95plusmn 03 cm) were purchased from Luchaogang freshmarket Shanghai Crayfish were transported in a foam-padded box with ice to the lab in 2 hours 0en the crayfishwere cleaned with ice water the heads and shells wereremoved and then they were washed with ice distilledwater0e deshelled crayfish were randomly assigned to thefive following batches (1) uncoated (control CK) (2)treated with gelatin solution containing 01 (wv) ε-PLwithout RPPE (T0) (3) treated with gelatin solutioncontaining 01 (wv) ε-PL with 1 RPPE (T1) (4) treatedwith gelatin solution containing 01 (wv) ε-PL with 2RPPE (T2) (5) treated with gelatin solution containing01 (wv) ε-PL with 3 RPPE (T3) 0e deshelled crayfishwere individually coated by immersing in the edible coatingfor 60 s (ratio of coating solution to crayfish 5 1) and thenthe coated samples were removed and allowed to drain at4degC for 20min to form the edible coatings 0e controlsamples were dipped in sterile purified water as othercoating solutions for 1min and then drained at 4degC 0e

2 Journal of Food Quality

treated crayfish samples were then packed in polyethylenebags and stored at 4plusmn 05degC for 8 days 0e experimentaldesign is shown in Figure 1 Physicochemical and watermigration analyses were performed at 0 2 4 6 7 and8 days of storage to study the progress of deterioration

27 Physicochemical Analysis

271 pH and Conductivity Measurement 0e pH mea-surement and conductivity were determined according toKim et al [22] using the pH meter (PB-10 SartoriusGermany) and conductivity meter (FE30 Mettler ToledoShanghai China)

272 K Value 0e K value was determined according toFang et al [23]

273 Determination of Total Volatile Basic Nitrogen (TVB-N)0e TVB-N values were determined according to Shi et al[24] and the TVB-N values of crayfish samples wereexpressed in mgN100 g

274 Determination of Free Amino Acids (FAAs) 0e FAAswere measured by the method according to Yu et al [25]using the automatic amino acid analyzer (L 8800 HitachiLtd Japan)

28 LF NMR Analysis LF NMR analysis was performedaccording to the method of Li et al [26] Portions of05times 05times 02 cm (about 1 g) were cut from the dorsal part ofcrayfish and sealed with polyethylene films 0e sampleswere placed in NMR tubes (70mm diameter) T2 mea-surements were recorded on a LF NMR analyzer (Mes-oMR23-060HI Newmai co Ltd CA) with a protonresonance frequency of 20MHz and the primary parameterswere as follows SW 100 kHz RFD 008 NS 4P1 18 μs P2 36 μs RG1 20 dB DRG1 6 dBPRG 0 delay DL1 02ms and TW 2000ms Longitu-dinal relaxation T1 was measured by using the inversion-recovery sequence by the following parameters P1 18 μsP2 36 μs SW 200KHz RFD 0020ms RG1 20 dBDRG1 1 NS 4 TW 5000ms PRG 0 NTI 20 andDL1 02ms

29 SEM Pieces of 30 times 50mm muscle tissue were cutfrom the sample fixed with 25 glutaraldehyde for 2 h at4degC and then washed with phosphate buffer (pH 72) threetimes Gradient elution with 50 70 80 90 95 and 100ethanol was performed for 15min respectively Micro-structure observations of surface were carried out using aSEM S-3400N (Hitachi Japan)

210 Statistical Analysis 0e one-way ANOVA procedurefollowed by Duncanrsquos multiple range tests was adopted todetermine the significant difference (plt 005) among

treatment means and the results were expressed asmeans plusmn SD

3 Results and Discussion

31 Antioxidant Activity of Preservative Solutions 0e totalphenolic contents of RPPE were 453478mg of GAE100 g ofRPPE and the betanin presented 5585mg100 g0e DPPHradical scavenging was 1814 2419 3181 and 3854for T0 T1 T2 and T3 solutions respectively 0ese resultsdemonstrated that the higher RPPE addition showed ahigher antioxidant activity in the coating solutions 0isbehavior was also observed where the samples containingwith higher RPPE addition presented higher values of an-tioxidant activity 0e ABTS radical scavenging for ediblecoatings solutions with 1 2 and 3 RPPE was 019 032and 039mM Trolox equivalent respectively and the CKand T0 had no antioxidant activity 0is was similar to theresult of DPPH radical scavenging in pomegranate peelextract- (PPE-) incorporated zein film [27] 0e DPPHradical scavenging was about 40 for film-25mg PPE RPPEmay be a good substitute for synthetic antioxidants and theresults also demonstrated that the RPPE presents antioxi-dant activity when added to the edible coating solutions

32 pH and Electrical Conductivity Analysis 0e changes inpH of crayfish are shown in Figure 2(a) 0e initial pH value

Salmon skin gelatin powder

Freeze-dried red pitaya peel

Freeze-dried red pitaya peelmethanol extract powder

Figure 1 Application of gelatin-based edible coating containingred pitaya peel methanol extract on deshelled crayfish at day 0

Journal of Food Quality 3

was 665 and it is similar to that of white shrimp [28] 0epH of CK and T0 samples significantly decreased (plt 005)at first and then increased from day 2 to the end Howeverthe pH of T1 T2 and T3 samples significantly decreased(plt 005) from day 0 to day 4 and then tended to increase0e decrease in pH may due to the lactic acid produced bythe glycolysis of glycogen [29] During refrigerated storagethe volatile compounds such as trimethylamine dimethyl-amine and ammonia produced by proteolysis led to theincrease of pH [30]0is result was consistent with the resultof Wang et al using chitosan-carvacrol coating on thequality of Pacific white shrimp during iced storage [31]Electrical conductivity is an index of the concentration ofelectrolytes in the muscle tissue and it can be used tocharacterize the texture of sample tissue [32] 0e electricalconductivity value of all samples increased significantly(plt 005) while the CK and T0 samples showed highervalues during storage (Figure 2(b))0e RPPE could slow theelectrical conductivity increase which may be due to ionic

substances produced by bacteria and decomposed muscletissues [33]

33 TVB-N Analysis TVB-N value could assess the qualityof freshwater products during storage and its increase isclosely associated with the degradation of protein or non-protein nitrogenous compounds by the activities of spoilagebacteria and endogenous enzymes [34] 0e TVB-N value ofdeshelled crayfish at day 0 was 458mg100 g and it con-tinually increased in all the samples during storage(Figure 2(c)) 0e CK showed significantly higher valuesthan T1 T2 and T3 (plt 005) Generally 20mg100 g is therejection limit for TVB-N values in freshwater products [35]and the TVB-N value in CK and T0 reached to an un-accepted level (3113mg100 g and 2032mg100 g re-spectively) at day 6 Samples with bioactive edible coatingcontaining RPPE had lower TVB-N values compared withCK and T0 T1 reached the unaccepted level at day 7 and T2

2 4 60 8Storage time (day)

60

62

64

66

68

70

72

74

76

78

pH

CKT0T1

T2T3

(a)


CKT0T1

T2T3

0

100

200

300

400

500

600

700

800

Δcon

duct

ivity

(con

duct

ivity

ndash in

itial

cond

uctiv

ity) (micros

cm

)

(b)


CKT0T1

T2T3

0

5

10

15

20

25

30

35

40

45

TVB-

N (m

g10

0g)

(c)


CKT0T1

T2T3

0

20

40

60

80K

valu

e (

)

(d)

Figure 2 Change in pH values electrical conductivity TVB-N and K value of crayfish during storage at 4degC


and T3 reached the unaccepted level at day 8 0e RPPEcould delay the increase of TVB-N effectively leading to alonger shelf life of deshelled crayfish 0is is in agreementwith the research reported byMorsy using pomegranate peelto improve the quality attributes of meatballs [36]

34 K Value Analysis K value is an effective and reliableindex for freshness evaluation of freshwater products [11]0e initial K value in samples was 613 (Figure 2(d)) and agradual increase in K value was observed with storage timewhich suggested that fish gelatin edible coating containingRPPE could keep the freshness in crayfish muscle duringstorage 0e K value of all samples increased significantly(plt 005) while the CK showed higher values duringstorage0e K value in CK T0 T1 T2 and T3 exceeded 70(considered to be unacceptable [37]) after 6 7 and 8 days ofstorage respectively 0is result was similar to the shelf lifeextension of crucian carp using natural preservatives duringchilled storage [38]

35 LF-NMR NMR transverse relaxation T2 indicates threedifferent types of water which are as follows the boundwater entrapped within tertiary and quaternary proteinstructures immobile water within the myofibril and freewater in the extramyofibrillar space corresponding to T21(001 to 10 s) T22 (10 to 100ms) and T23 (100 to 1000ms)

respectively [24] Furthermore the integral area of differenttransversal relaxation times in the percentage of the totalintegral area could reflect the content of different forms ofwater [39] In the research T21 changed slightly for all thesamples however T22 decreased and T23 fluctuated withoutregular trends during storage 0is result indicated that thechanges of free water were more obvious than those ofbound and immobile water in deshelled crayfish sampleswith the storage time pT21 pT22 and pT23 corresponded tothe areas of relaxation times T21 T22 and T23 (Table 1)Obviously pT21 and pT23 increased observably howeverpT22 diminished progressively during storage and pT22took the largest proportion of three types of water Nosignificant differences (pgt 005) was detected among theimmobilized water in T3 compared with other samplesprobably due to that more RPPE addition could retard theimmobilized water within the myofibril to free water andkeep excellent quality of crayfish muscle

36 FAAAnalysis FAAs are responsible for the formation offlavor and can be the precursor of aromatic compounds 0eincrease of FAA content is due to protein and peptide de-composition induced by proteolytic enzymes while its de-crease is due to the reaction of these amino acids with othercompounds [40] 0e major FAAs in deshelled crayfish wereArg 0r Ala and Gly which accounted for 7608ndash8792 oftotal FAAs (Table 2) As a flavor-stale amino acid His of CK

Table 1 Changes of transverse relaxation time and water distribution of crayfish during storage

Storage time (day) T21 T22 T23 pT21 pT22 pT23

0d075plusmn 005abc 6579plusmn 263a 46416plusmn 1928a 114plusmn 001ab 9758plusmn 004a 128plusmn 001ab

2dCK 132plusmn 004de 6579plusmn 263a 53367plusmn 3736b 105plusmn 001bc 9638plusmn 009b 257plusmn 007cT0 132plusmn 005de 7565plusmn 605b 70548plusmn 2822c 124plusmn 004ad 9704plusmn 003c 172plusmn 007deT1 134plusmn 043de 7565plusmn 227b 53367plusmn 4803b 099plusmn 008c 9739plusmn 002d 162plusmn 009eT2 114plusmn 049ef 6579plusmn 197a 46416plusmn 452a 130plusmn 001de 9725plusmn 004e 145plusmn 009fT3 076plusmn 002abc 7565plusmn 151b 73820plusmn 2145c 141plusmn 009f 9724plusmn 004e 135plusmn 004a

4dCK 152plusmn 014dg 5722plusmn 387c 40370plusmn 3230ae 243plusmn 009g 9504plusmn 008f 253plusmn 005cT0 152plusmn 009dg 6579plusmn 395a 53367plusmn 4803b 185plusmn 004h 9625plusmn 003g 190plusmn 005gT1 104plusmn 008aef 5722plusmn 051c 46416plusmn 1392a 233plusmn 008i 9616plusmn 006g 151plusmn 004fT2 114plusmn 025ef 6579plusmn 329a 46416plusmn 455a 124plusmn 010ad 9753plusmn 009a 123plusmn 007bT3 072plusmn 007abc 5722plusmn 286c 35112plusmn 2458e 138plusmn 007ef 9749plusmn 003a 113plusmn 008h

6dCK 043plusmn 001c 4977plusmn 098d 40370plusmn 1615ae 207plusmn 003j 9457plusmn 003h 337plusmn 004iT0 134plusmn 027de 7565plusmn 752b 61359plusmn 3682d 186plusmn 005h 9562plusmn 004i 251plusmn 002cT1 087plusmn 002abf 5722plusmn 172c 53367plusmn 3670b 208plusmn 007j 9559plusmn 003i 232plusmn 004jT2 175plusmn 012gh 5722plusmn 256c 46416plusmn 2633a 133plusmn 008def 9694plusmn 008j 173plusmn 009dT3 066plusmn 001bc 6579plusmn 395a 61359plusmn 3068d 143plusmn 003fk 9581plusmn 002k 076plusmn 008k

7dT1 115plusmn 005ef 4329plusmn 087e 40370plusmn 755ae 247plusmn 005g 9479plusmn 006l 269plusmn 001lT2 201plusmn 016h 7565plusmn 302b 61359plusmn 4908d 163plusmn 005l 9617plusmn 002g 219plusmn 002mT3 175plusmn 013gh 6579plusmn 552a 46416plusmn 928a 152plusmn 008k 9653plusmn 005m 200plusmn 006n

8dT2 152plusmn 014dg 6579plusmn 197a 46416plusmn 326a 192plusmn 004h 9604plusmn 006n 205plusmn 005nT3 066plusmn 007bc 5722plusmn 036c 40307plusmn 1897ae 108plusmn 003bc 9127plusmn 009e 164plusmn 005de

Means in the same column with different letters are significantly different (plt 005)


increased from the initial value of 2343mg100 g to3002mg100 g at day 4 while the content of T0 T1 T2 andT3 were 4270 3325 3610 and 3178mg100 g at day 8respectively His was basically caused by the oxidation processfrom trimethylamine oxide based on the growth of thespoilage organism and was consistent with results of the TVB-N value Arg 0r Met Ile and Lys showed upwards trends atthe early storage and afterwards gradually decreased howeverAsp Glu Tyr and His showed upwards Ala and Gly pro-gressively decreased during storage which was owing to the

positive enhancing effects of desired tastes and characterizedby sweetness [41 42]0e decrease of special flavor-enhancingamino acids and accumulation of flavor-detracting aminoacids could lead to the flavor deterioration and the coatingwith RPPE could effectively slow down the process andmaintain the quality of deshelled crayfish

37 Microstructure of Crayfish Muscle Representative SEMmicrostructures of crayfish muscle subjected to the RPPEtreatments were compared with fresh crayfish muscle in

Table 2 FAA contents of crayfish sample during storage at 4degC

FAA (mg100 g) 0d 4d 8d0d CK T0 T1 T2 T3 T0 T1 T2 T3

Asp 023 074 112 135 059 110 213 128 197 1550r 14862 8368 10436 7456 5979 8313 10388 7988 10168 12319Ser 5023 mdash mdash mdash 787 435 1026 mdash mdash 1524Glu 966 1702 1507 1858 898 1250 2312 7940 2125 1761Gly 5498 3437 5825 2450 1962 5415 3149 5480 2762 3887Ala 12700 7476 11867 7978 7255 8703 9612 12567 9326 8641Val 1870 1727 1821 1606 1002 1601 2453 1450 2172 2060Met 1654 1215 1158 1238 729 783 1412 1506 1173 1152Ile 980 618 697 648 536 741 1065 622 976 1039Leu 1780 1222 1312 1156 927 1297 1882 1131 1845 1895Tyr 497 590 558 489 446 434 775 734 675 565Phe 553 621 570 666 444 454 1118 628 985 646Lys 2995 795 2017 1097 1933 1404 1754 3211 1627 3964His 2343 3505 3002 3349 2099 2598 4270 3325 3610 3178Arg 61635 44914 49742 50177 44901 44067 53066 42967 47256 58479Total 113378 76264 90624 80303 69956 77605 94498 89677 84897 101265mdash not detected

Figure 3 SEM images of crayfish under different treatments during storage (a) At the beginning (b) CK at 8th day (c) T0 at 8th day (d) T1at 8th day (e) T2 at 8th day (f ) T3 at 8th day


Figure 3 We observed significant differences between thefresh crayfish muscle and those treated with RPPE both infibers bundles and intramuscular connective tissues At day0 fresh crayfish had a complete and smooth muscle structureand a compact muscle fiber arrangement (Figure 3) Somesmall spaces appeared between the muscle bundles in thefresh sample all of which indicated a well-organized struc-ture With the prolongation of storage time the muscle fibertissues in the treated groups had different degrees of de-terioration At day 8 the muscle structure of the CK and T0samples were most degraded and the surface texture was looseand fuzzy Although degradation was also observed in the T1and T2 samples the fibers bundles and structures were stillregular in appearance 0e muscle fiber of T3 was moreregular and themuscle fiber was not significantly broken0econnective tissues also adhered to each other tightly whichwere very similar to those of the fresh sample 0ereforeRPPE delayed the degradation of crayfish muscle

4 Conclusion

RPPE exhibited a high amount of total phenolic anddemonstrated effective antioxidant properties Gelatincoating with RPPE and ε-PL delayed deshelled crayfishdeterioration in quality parameters such as TVB-N K valueFAAs and water migration and could extend deshelledcrayfish shelf life by 2 days Combined with the effect of thecolor of the preservation solution on the samples the coatingcombined with 20 RPPE was preferred

Data Availability

0e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

0e authors declare no conflicts of interest

Acknowledgments

0e authors would like to express their profound gratitude toWeiqiang Qiu from the Instrumental Analysis Center ofShanghai Ocean University for his technical assistance 0isresearch was funded by the NSFC (31571914 and 31601414)China Agriculture Research System (CARS-47) National KeyResearch and Development Program (2016YFD0400106)Doctoral Start-Up Fund from SHOU and ConstructionProject of Public Service Platform for Shanghai MunicipalScience and Technology Commission (17DZ2293400)

References

[1] M Z Elsabee E S Abdou K S A Nagy and M EweisldquoSurface modification of polypropylene films by chitosan andchitosanpectin multilayerrdquo Carbohydrate Polymers vol 71no 2 pp 187ndash195 2008

[2] Y Shao G Xiong J Ling et al ldquoEffect of ultra-high pressuretreatment on shucking and meat properties of red swampcrayfish (Procambarus clarkia)rdquo LWT vol 87 pp 234ndash2402018

[3] G Chen and Y L Xiong ldquoShelf-stability enhancement ofprecooked red claw crayfish (Cherax quadricarinatus) tails bymodified CO2O2N2 gas packagingrdquo LWTmdashFood Science andTechnology vol 41 no 8 pp 1431ndash1436 2008

[4] O Cremades C Alvarez-ossorio J F Gutierrez-GilJ Parrado and J Bautista ldquoQuality changes of cooked crayfish(Procambarus clarkii) tails without additives during storageunder protective atmospheresrdquo Journal of Food Processingand Preservation vol 35 no 6 pp 898ndash906 2011

[5] C G Hernandez-Valencia A Roman-Guerrero A Aguilar-Santamarıa L Cira and K Shirai ldquoCross-linking chitosaninto hydroxypropylmethylcellulose for the preparation ofneem oil coating for postharvest storage of pitaya (Stenocereuspruinosus)rdquo Molecules vol 24 no 2 p 219 2019

[6] P Fan D J Huber Z Su et al ldquoEffect of postharvest spray ofapple polyphenols on the quality of fresh-cut red pitaya fruitduring shelf liferdquo Food Chemistry vol 243 pp 19ndash25 2018

[7] M Amid Y Manap and N Zohdi ldquoA novel aqueous twophase system composed of a thermo-separating polymer andan organic solvent for purification of thermo-acidic amylaseenzyme from red pitaya (Hylocereus polyrhizus) peelrdquo Mol-ecules vol 19 no 5 pp 6635ndash6650 2014

[8] H Kim H-K Choi J Y Moon Y S Kim A Mosaddik andS K Cho ldquoComparative antioxidant and antiproliferativeactivities of red and white pitayas and their correlation withflavonoid and polyphenol contentrdquo Journal of Food Sciencevol 76 no 1 pp C38ndashC45 2011

[9] B Jamilah C E Shu M Kharidah M A Dzulkifly andA Noranizan ldquoPhysico-chemical characteristics of red pitaya(Hylocereus polyrhizus) peelrdquo International Food ResearchJournal vol 18 no 1 pp 279ndash286 2011

[10] F Ferreres C Grosso A Gil-Izquierdo P ValentatildeoA T Mota and P B Andrade ldquoOptimization of the recoveryof high-value compounds from pitaya fruit by-products usingmicrowave-assisted extractionrdquo Food Chemistry vol 230pp 463ndash474 2017

[11] Q He and K Xiao ldquo0e effects of tangerine peel (Citrireticulatae pericarpium) essential oils as glazing layer onfreshness preservation of bream (Megalobrama amblyce-phala) during superchilling storagerdquo Food Control vol 69pp 339ndash345 2016

[12] A N Adilah B Jamilah M A Noranizan andZ A N Hanani ldquoUtilization of mango peel extracts on thebiodegradable films for active packagingrdquo Food Packaging andShelf Life vol 16 pp 1ndash7 2018

[13] Z Shad H Mirhosseini A S M Hussin B ForghaniM Motshakeri and M Y A Manap ldquoAqueous two-phasepurification of α-amylase from white pitaya (Hylocereusundatus) peel in polyethylene glycolcitrate system optimi-zation by response surface methodologyrdquo Biocatalysis andAgricultural Biotechnology vol 14 pp 305ndash313 2018

[14] X Carrion-Granda I Fernandez-Pan J Rovira and J I MateldquoEffect of antimicrobial edible coatings and modified atmo-sphere packaging on themicrobiological quality of cold storedhake (Merluccius merluccius) filletsrdquo Journal of Food Qualityvol 2018 Article ID 6194906 12 pages 2018

[15] E Choulitoudi S Ganiari T Tsironi et al ldquoEdible coatingenriched with rosemary extracts to enhance oxidative andmicrobial stability of smoked eel filletsrdquo Food Packaging andShelf Life vol 12 pp 107ndash113 2017

[16] M S Alsagga S H Moussa and A A Tayel ldquoApplication offungal chitosan incorporated with pomegranate peel extract asedible coating for microbiological chemical and sensorialquality enhancement of Nile tilapia filletsrdquo International


Journal of Biological Macromolecules vol 99 pp 499ndash5052017

[17] G Lisa T Catrin and M Alessandra ldquoEffect of processing onantioxidant activity total phenols and total flavonoids ofpigmented heirloom beansrdquo Journal of Food Qualityvol 2018 Article ID 7836745 6 pages 2018

[18] F R de Mello C Bernardo C O Dias et al ldquoAntioxidantproperties quantification and stability of betalains frompitaya (Hylocereus undatus) peelrdquo Ciencia Rural vol 45no 2 pp 323ndash328 2014

[19] J Tkaczewska M Morawska P Kulawik and M ZajacldquoCharacterization of carp (Cyprinus carpio) skin gelatinextracted using different pretreatments methodrdquo Food Hy-drocolloids vol 81 pp 169ndash179 2018

[20] A Mansour R Celano T Mencherini et al ldquoA new cineolderivative polyphenols and norterpenoids from Saharanmyrtle tea (Myrtus nivellei) isolation structure de-termination quantitative determination and antioxidant ac-tivityrdquo Fitoterapia vol 119 pp 32ndash39 2017

[21] S-D Zhou X Xu Y-F Lin H-Y Xia L Huang andM-S Dong ldquoOn-line screening and identification of freeradical scavenging compounds in Angelica dahurica fer-mented with Eurotium cristatum using an HPLC-PDA-triple-TOF-MSMS-ABTS systemrdquo Food Chemistry vol 272pp 670ndash678 2019

[22] J-H KimW-S Hong and S-W Oh ldquoEffect of layer-by-layerantimicrobial edible coating of alginate and chitosan withgrapefruit seed extract for shelf-life extension of shrimp(Litopenaeus vannamei) stored at 4degCrdquo International Journalof Biological Macromolecules vol 120 pp 1468ndash1473 2018

[23] Z Fang L Zhou Y Wang L Sun and R GooneratneldquoEvaluation the effect of mycotoxins on shrimp (Litopenaeusvannamei) muscle and their limited exposure dose for pre-serving the shrimp qualityrdquo Journal of Food Processing andPreservation vol 43 no 4 article e13902 2019

[24] J Shi Y Lei H Shen et al ldquoEffect of glazing and rosemary(Rosmarinus officinalis) extract on preservation of mudshrimp (Solenocera melantho) during frozen storagerdquo FoodChemistry vol 272 pp 604ndash612 2019

[25] D Yu Y Xu J M Regenstein et al ldquo0e effects of ediblechitosan-based coatings on flavor quality of raw grass carp(Ctenopharyngodon idellus) fillets during refrigerated stor-agerdquo Food Chemistry vol 242 pp 412ndash420 2018

[26] N Li Y Shen W Liu J Mei and J Xie ldquoLow-field NMR andMRI to analyze the effect of edible coating incorporated withMAP on qualities of half-smooth tongue sole (Cynoglossussemilaevis gunther) fillets during refrigerated storagerdquoAppliedSciences vol 8 no 8 p 1391 2018

[27] M Mushtaq A Gani A Gani H A Punoo andF A Masoodi ldquoUse of pomegranate peel extract incorporatedzein film with improved properties for prolonged shelf life offresh Himalayan cheese (Kalarikradi)rdquo Innovative FoodScience amp Emerging Technologies vol 48 pp 25ndash32 2018

[28] M Jiang S Liu and Y Wang ldquoEffects of antimicrobialcoating from catfish skin gelatin on quality and shelf life offresh white shrimp (Penaeus vannamei)rdquo Journal of FoodScience vol 76 no 3 pp M204ndashM209 2011

[29] D Yu Q Jiang Y Xu andW Xia ldquo0e shelf life extension ofrefrigerated grass carp (Ctenopharyngodon idellus) fillets bychitosan coating combined with glycerol monolauraterdquo In-ternational Journal of Biological Macromolecules vol 101pp 448ndash454 2017

[30] J Jian L Liao Y Qiao et al ldquo0e effects of vacuum packagecombined with tea polyphenols (V+TP) treatment on quality

enhancement of weever (Micropterus salmoides) stored at 0degCand 4degCrdquo LWT-Food Science and Technology vol 91pp 484ndash490 2018

[31] Q Wang J Lei J Ma G Yuan and H Sun ldquoEffect ofchitosan-carvacrol coating on the quality of pacific whiteshrimp during iced storage as affected by caprylic acidrdquo In-ternational Journal of Biological Macromolecules vol 106pp 123ndash129 2018

[32] H Fan Y Luo X Yin Y Bao and L Feng ldquoBiogenic amineand quality changes in lightly salt-and sugar-salted black carp(Mylopharyngodon piceus) fillets stored at 4degCrdquo FoodChemistry vol 159 pp 20ndash28 2014

[33] Z Xu X Liu H Wang H Hong and Y Luo ldquoComparisonbetween the Arrhenius model and the radial basis functionneural network (RBFNN) model for predicting qualitychanges of frozen shrimp (Solenocera melantho)rdquo In-ternational Journal of Food Properties vol 20 no 11pp 2711ndash2723 2017

[34] S Wu ldquoEffect of chitosan-based edible coating on preser-vation of white shrimp during partially frozen storagerdquo In-ternational Journal of Biological Macromolecules vol 65pp 325ndash328 2014

[35] J Sun R Zhang Y Zhang et al ldquoClassifying fish freshnessaccording to the relationship between EIS parameters andspoilage stagesrdquo Journal of Food Engineering vol 219pp 101ndash110 2018

[36] M K Morsy E Mekawi and R Elsabagh ldquoImpact ofpomegranate peel nanoparticles on quality attributes ofmeatballs during refrigerated storagerdquo LWT vol 89pp 489ndash495 2018

[37] T Saito K-I Arai and M Matsuyoshi ldquoA new method forestimating the freshness of fishrdquo Nippon Suisan Gakkaishivol 24 no 9 pp 749-750 1959

[38] T Li J Li W Hu X Zhang X Li and J Zhao ldquoShelf-lifeextension of crucian carp (Carassius auratus) using naturalpreservatives during chilled storagerdquo Food Chemistryvol 135 no 1 pp 140ndash145 2012

[39] T Li Y Jiang G Jin Q Zhao and J Li ldquoEffects of fish-derived biological preservatives on cold storage of grass carp(Ctenopharyngodon idellus) filletsrdquo Journal of Food Protectionvol 79 no 10 pp 1707ndash1716 2016

[40] X Yin Y Luo H Fan HWu and L Feng ldquoEffect of previousfrozen storage on quality changes of grass carp (Ctenophar-yngodon idellus) fillets during short-term chilled storagerdquoInternational Journal of Food Science amp Technology vol 49no 6 pp 1449ndash1460 2014

[41] K Itou and Y Akahane ldquoChanges in proximate compositionand extractive components of rice-bran-fermented mackerelheshiko during processingrdquoNippon Suisan Gakkaishi vol 66no 6 pp 1051ndash1058 2000

[42] M Takahashi N Hirose S Ohno M Arakaki and K WadaldquoFlavor characteristics and antioxidant capacities of hihat-sumodoki (Piper retrofractum vahl) fresh fruit at three ediblematurity stagesrdquo Journal of Food Science and Technologyvol 55 no 4 pp 1295ndash1305 2018


Hindawiwwwhindawicom

International Journal of

Volume 2018

Zoology

Hindawiwwwhindawicom Volume 2018

Anatomy Research International

PeptidesInternational Journal of



Journal of Parasitology Research

GenomicsInternational Journal of


Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018


BioinformaticsAdvances in

Marine BiologyJournal of



Neuroscience Journal


BioMed Research International

Cell BiologyInternational Journal of



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ArchaeaHindawiwwwhindawicom Volume 2018


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Enzyme Research



MicrobiologyHindawiwwwhindawicom

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Volume 2018

Submit your manuscripts atwwwhindawicom

polyphenols from apple peels [6 11 12] Edible coating canbe used to protect phenolic compounds from oxidation byexternal factors such as the presence of light oxygen metalions pH and high temperatures [13] and provide freshfood protection to prevent quality loss and weight lossSeveral researchers have applied it to the storage of aquaticproducts [14ndash16]

In this study we investigated the effect of the additionand the level (10 20 and 30 (wv)) of red pitaya peelextract (RPPE) combined with 01 ε-PL on the physico-chemical and water migration of deshelled crayfish stored at4degC under aerobic condition

2 Materials and Methods

21 Preparation of RPPE Fresh red pitaya fruits were ob-tained from the producer in Zhanjiang China and the peelwas manually separated lyophilized for 48 h and milled in acommercial blender (WBL1022S Guangdong Midea Elec-tric Appliances Co Ltd China) 0e fine powder siftedthrough a 40-mesh sieve was collected and stored in anamber flask 0e powder (250 g) was mixed with 200mL ofmethanol and water (80 20 vv) solution and then trans-ferred to an ultrasonic extractor (KQ-100DE KunshanUltrasound Instrument Co Jiangsu China) at a power of240W for 30min After extraction the solution wascentrifuged at 3100 times g for 15min at 4degC and the super-natant was transferred to an amber flask 0e extract wasconcentrated using a rotary evaporator (RE-5299 ShanghaiYarong Biochemical Instrument Factory Shanghai China)at 50 rpm and 40degC under vacuum to remove methanol andthen freeze-dried 0e freeze-dried RPPE powder sampleswere stored at 4degC in the dark [8]

22 Determination of Polyphenols of RPPE

221 Total Polyphenolic Content 0e total polyphenoliccontent was determined by the FolinndashCiocalteu colorimetricmethod based on oxidationreduction reactions of phenolsand the results were expressed as milligram gallic acidequivalent per gram dry weight (mgmiddotGAEgmiddotdw) of RPPEpowder [17]

222 Determination of Betacyanin Content 0e absorbanceof betacyanin was determined using the method describedby de Mello et al [18] Quantification of betalains wascalculated by the following equation

betacyanin contentmg100 g

1113888 1113889 A times DF times MW times V times 100

ε times L times W

(1)

where A is the absorption value at 538 nm DF is the dilutionfactor MW is the molecular weight of betanin (550 gmol)V is the pigment solution volume (mL) ε is the molarextinction coefficients of betanin (60000 Lmiddotmolminus1middotcmminus1) L isthe path length of the cuvette and W is the weight ofpigment powder (g)

23 Extraction of Salmon Skin Gelatin 0is method de-scribed by Tkaczewska et al [19] was used with somemodifications 0e salmon skins were cut into small pieces(5times 5 cm) and poured into water to remove adhesive im-purities and soaked in 005molmiddotLminus1 sodium hydroxide for2 h at a samplealkali solution ratio of 1 6 (wv) 0en skinswere washedwith distilled water at 4degC until neutral to removethe remaining alkali soaked in 005molmiddotLminus1 acetic acid for 2 hat a sampleacid solution ratio of 1 6 (wv) and then alsowashed to neutrality at 4degC 0e pretreated skins wereextracted with distilled water at 50degC for 6 h and the mixturewas filtered and then lyophilized to obtain the gelatin sample

24 Preparation of Preservative Solutions Gelatin solution(12 (wv)) was prepared by dispersing gelatin in distilledwater at 60degC and stirring for 3h After dissolved completelythe solution was filtered with cheesecloth and then 01 ε-PLwas added and the mixture was homogenized at 30k rpm for60 s All the edible coating solutions (G gelatin solutioncontaining 01 (wv) ε-PL G-1 RPPE gelatin solutioncontaining 01 (wv) ε-PL and 1 RPPE G-2 RPPE gelatinsolution containing 01 (wv) ε-PL and 2 RPPE G-3RPPE gelatin solution containing 01 (wv) ε-PL and 3RPPE)were prepared and adjusted to pH70 Finally a vacuumpump was applied to remove air bubbles from the solutions

25 Determination of Antioxidant Activity of PreservativeSolutions 0e antiradical activities of preservative solutionswere determined using the stable radical DPPH (22diphenyl-1-picrylhydrazyl) according to Mansour et al [20]0e ABTS (22prime-azino-bis(3-ethylbenzothiazoline-6-sul-phonic acid)) radical-scavenging activity was conductedusing the method described by Zhou et al [21] 0e anti-oxidant capacity of the sample was expressed in terms of themolar concentration of the standard

26 Preparation and Treatment of Crayfish Samples Freshred swamp crayfish (Procambarus clarkii) in the same size(95plusmn 03 cm) were purchased from Luchaogang freshmarket Shanghai Crayfish were transported in a foam-padded box with ice to the lab in 2 hours 0en the crayfishwere cleaned with ice water the heads and shells wereremoved and then they were washed with ice distilledwater0e deshelled crayfish were randomly assigned to thefive following batches (1) uncoated (control CK) (2)treated with gelatin solution containing 01 (wv) ε-PLwithout RPPE (T0) (3) treated with gelatin solutioncontaining 01 (wv) ε-PL with 1 RPPE (T1) (4) treatedwith gelatin solution containing 01 (wv) ε-PL with 2RPPE (T2) (5) treated with gelatin solution containing01 (wv) ε-PL with 3 RPPE (T3) 0e deshelled crayfishwere individually coated by immersing in the edible coatingfor 60 s (ratio of coating solution to crayfish 5 1) and thenthe coated samples were removed and allowed to drain at4degC for 20min to form the edible coatings 0e controlsamples were dipped in sterile purified water as othercoating solutions for 1min and then drained at 4degC 0e
























60

62

64

66

68

70

72

74

76

78

pH

CKT0T1

T2T3

(a)


CKT0T1

T2T3

0

100

200

300

400

500

600

700

800

Δcon

duct

ivity

(con

duct

ivity

ndash in

itial

cond

uctiv

ity) (micros

cm

)

(b)


CKT0T1

T2T3

0

5

10

15

20

25

30

35

40

45

TVB-

N (m

g10

0g)

(c)


CKT0T1

T2T3

0

20

40

60

80K

valu

e (

)

(d)



























4 Conclusion


Data Availability




Acknowledgments


References

















































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018
























60

62

64

66

68

70

72

74

76

78

pH

CKT0T1

T2T3

(a)


CKT0T1

T2T3

0

100

200

300

400

500

600

700

800

Δcon

duct

ivity

(con

duct

ivity

ndash in

itial

cond

uctiv

ity) (micros

cm

)

(b)


CKT0T1

T2T3

0

5

10

15

20

25

30

35

40

45

TVB-

N (m

g10

0g)

(c)


CKT0T1

T2T3

0

20

40

60

80K

valu

e (

)

(d)



























4 Conclusion


Data Availability




Acknowledgments


References

















































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018


























4 Conclusion


Data Availability




Acknowledgments


References

















































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018

































Volume 2018

Zoology











Volume 2018

















Advances in




Enzyme Research





Volume 2018


application of gelatin incorporated with red pitaya peel...

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