Comparative Study on Quality Attributes of Vacuum and Atmospheric Fried Bitter Gourd Chips

The correlation between increased vegetable consumption and protection against chronic diseases as well as a shift towards sustainable and personalized food choices has motivated interest in production of value-added products from vegetables. In this study bitter gourd slices were vacuum fried at three different temperatures 90, 100 and 115 °C at vacuum pressure 9 kPa. The prepared chips were analyzed for quality attributes such as oil content, total phenolic content, crude fibre, colour, texture, browning index. The sensory evaluation of vacuum fried bitter gourd chips fried at 115 °C and 9 kPa scored highest points 8.02 among all other samples on nine point hedonic scales. The composition of vacuum fried bitter gourd chips showed 21.67% oil, 11.52% crude fibre and 3828 mg/100 gm total phenolic content. The colour was measured using Lovibond RT 300 portable reflectance spectrophotometer, and the colour values L*, a* and b* were 57.67, 10.76 and 34.09 respectively. The scanning electron micrograph of vacuum fried bitter gourd chips reveals the presence of more porous structure compared to atmospherically fried chips. The moisture sorption isotherm for vacuum fried bitter gourd chips at 38 °C showed typical type II sigmoid shape. Sorption isotherm model equations such as Brumauer–Emmet–Teller (BET), Smith, Halsey, Oswin, Henderson, Kuhn, Iglesias and Chirife, and Freundlich applied for the fitting of experimental moisture sorption data yielded high coefficient of determination R2 ranging from 0.96 to 0.99 confirming the applicability of the equations employed for modelling the process. The study indicates the feasibility of developing vacuum fried bitter gourd chips with high nutritional values and desired quality attributes.