changes in the colour kinetics of pantoa during deep fat frying
TRANSCRIPT
Colour Kinetics of Pantoa during Deep fat FryingNeethu, K.C., Magdaline Eljeeva Emerald, F., Heartwin A. Pushpadass, Menon Rekha Ravindra, Jayaraj Rao, K. and Surendra Nath, B. National Dairy Research Institute, Southern Regional Station, Adugodi, Bangalore- 560 030. E-mail: [email protected]
Pantoa is an indigenous milk based sweetmeat popular in Eastern India. Frying is the key operation involved in the production of pantoa. Heat induced surface browning during frying is responsible for the desirable crust colour development in the product. The present study was carried out to evaluate the kinetics of colour changes during deep fat frying of pantoa. Pantoa was prepared by admixing khoa and chhana in the ratio of 4:5 along with refined wheat flour (3%), semolina (3%), arrowroot flour (3%), ground sugar (0.7%) and baking powder (0.3%) to a smooth homogenous dough. It was then rolled into balls of 15 g weight each and fried in refined sunflower oil at temperatures of 125, 135 and 145C for 8 min. Pantoa samples at every 30seconds intervals were scanned using a HP flatbed scanner and the images were imported into Adobe Photoshop to compute L*a*b* values. Crust colour was evaluated in terms of lightness value (L*), yellowness Index (YI) and total colour difference (E) and modeled with zero order, first order and fractional conversion first order kinetics. The temperature dependency of the model was described using Arrhenius relationship. Lightness showed a negative trend while yellowness index and total colour difference showed a positive trend with frying time at all the three temperatures studied. Lightness changes followed the first order kinetics whereas yellowness index and total colour changes followed the fractional conversion first order kinetics. The estimated activation energies for lightness, yellowness index and total color difference were 83.72, 52.92 and 83.65 kJmol-1, respectively. The corresponding frequency factors were 7.5x107, 2.4x104 and 2.0x108 s-1. The parameters obtained will be useful in predicting the colour changes in pantoa during deep fat frying.