Comparing Natural Pectin from Apples and Grapefruit in Strawberry Jam

Nicolle Brossard & Jennifer Morgan

Introduction

• Utilize waste materials• Natural, no chemicals

added• Allows for a completely

organic product• Promotes fiber intake• Natural source of

sweetener

• Pectin is a soluble fiber• Reduce cholesterol• Delay emptying of stomach• Promotes fullness• Helps avoid blood sugar

spikes

Background Information• Until early 1800’s, only options were pickling, salting, drying or

smoking food stuffs. They affected:– Taste, texture and nutritional value.

• French chef Nicolas Appert perfected his revolutionary bottling technique-Appert found that by enclosing provisions within a sealed bottle and boiling it, the food would keep indefinitely.

• 1860’s-canning was used for civil war soldiers• 1870’s-U.S. was lead exporter of canned goods• With the slow-food movement, organic food movement, and

increase in consumer demand for healthier food options compared to traditional commercial products.

Hypothesis

Based on evaluation of acceptability (texture, taste, overall) and rheology, the strawberry jams made with pectin derived from apples

and grapefruit will be equivalent to the manufactured, store bought pectin keeping all

other variables the same.

Methods• Extract Apple and Grapefruit Pectins• Prepare strawberries• Prepare jam • Reduce jam• Measure Results (objective and

subjective)

Extracting Apple Pectin

• Apple– Granny smith apples– Cut apples into 1” cubes

with peel and seeds (approx 2 quarts)– Add enough water to cover– Boil until soft and mushy, ~1 hour– Strain with

cheesecloth

Extracting Grapefruit Pectin

• Grapefruit– Peeled the rind– Cut off white pith– Cut pith into ½” pieces (approx ½ Lb)– Soak in ¼ C lemon juice for 1 hour– Add 2 C water and boil for 1 hour– Strain with cheesecloth

Strawberry Jam with Commercial Pectin• Wash strawberries and cut off hulls then pulse in food

processor.• Mix commercial pectin and lemon juice with strawberries

and boil mixture in a non reactive pot.• Add sugar and boil until the mixture reaches gel point• Remove top layer of film. • Can, process in water bath, and cool.

Strawberry Jam with Apple & Grapefruit Pectin

• Allow pureed strawberries to macerate in sugar for 8 hours

• Repeat cooking process used for jam with commercial pectin

• Equal parts of apple pectin and strawberry mixture• Equal parts of grapefruit pectin and strawberry mixture

AppleGrapefruit

Day 1 before reducing jam Day 2 after reducing jam

Apple

Grapefruit

Strawberry Jam with Apple & Grapefruit Pectin

Complications & Variations• Creating the strawberry jam with apple and grapefruit

pectin required alterations to the control recipe.– Altering sugar, pectin, and lemon juice amounts to

create a gel• Loss of gel required reduction of strawberry jams with

apple and grapefruit pectin– Color change, flavor more concentrated in jam with

grapefruit pectin

C A G

Objective Results

Type of Measurement

Commercial Pectin Jam

Apple Pectin Jam Grapefruit Pectin Jam

pH 3.5 3.0 2.5

Percent Sag 40% 40% 48%

Line Spread 5.62 5.25 8.5

Comparing Apples and Oranges…or grapefruit

Subjective Results

21%

63%

17%

Texture Preference

Commercial AppleGrapefruit

42%

46%

13%

Flavor Preference

Commercial AppleGrapefruit

46%

46%

8%

Overall Acceptability

Commercial AppleGrapefruit

Implications & Conclusions• Pectin can be derived from natural sources and still create a

suitable product that compares to commercial products.• Added soluble fiber from the apple pectin & reduced sugar

can create a product that would be preferred over a commercial strawberry jam for diabetic or weight-conscious consumers.

• Grapefruit may interact with medications and may not be a suitable product for all potential consumers.

• Orange pectin is feasible as an alternative for a different flavor profile.

References• Hinton, C. L. (January 01, 1940). The quantitative basis of pectin jelly formation

in relation to pH conditions. The Biochemical Journal, 34, 8-9.• Bennison, E. W., & Norris, F. W. (January 01, 1939). The pectic substances of

plants: The relation between jelly strength, viscosity and composition of various pectins. The Biochemical Journal, 33, 9, 1443-51.

• Lima, M.S., Paiva, E.P., Andrade, S.A.C., Paixao, J.A. Fruit pectins-A suitable tool for screening gelling properties using infrared spectroscopy. Food Hydrocolloids, Jan 2010, Issue 1, pg. 1-7.

• Sorensen, I., Pedersen, H. L., Willats, W.G.T., An array of possibilities for pectin. Carbohydrate research, Sep 2009, Issue 14, pg. 1872-1878.

• Carbonell, E., Costell, E. Duran, L. Fruit content influence on gel strength of strawberry and peach jams. Journal of food science, Sep 1991, Volume 56, Issue 5, pg. 1384-1387.

• Guichard, E., Issanchou, S., Descourvieres, A., Etievant, P. Pectin concentration, molecular weight, and degree of esterification: Influence on volatile composition and sensory characteristics of strawberry jam. Journal of food science. Nov 1991, Volume 56, Issue 6, pg. 1621-1627.

Questions ?