Effect of vacuum frying on quality attributes of pear ( Pyrus communis L) chips and blended oil

Abstract

Standardization of various parameters during vacuum frying of pear slices and the effect of vacuum frying on blended oil (Palmolein and Sesame oils, 60:40) were studied. Oil samples were evaluated after an alternative vacuum frying of 20 consecutive cycles. Results showed that optimum vacuum frying conditions were temperature 110°C, vacuum 74–98 mbar, and time 4.0–4.2 min that produced pear chips with moisture content ≤2.04%, oil uptake ≤21.73%, breaking force ≤6.79N, color L* ≤64.31, a* ≤4.81, b* ≤29.76, and whiteness index ≤54.29, whereas conventionally fried chips contain moisture content 1.03% wt/wt, oil uptake 44.83%, breaking force 11.23N, color L* 21.84, a* 6.83, b* 11.67, and whiteness index 20.68. The peroxide value, free fatty acids, atherogenicity, and thrombogenicity index of oil obtained after vacuum frying (≤5.28, ≤2.84, ≤0.57, and ≤ 1.08, respectively) were found to be lower than conventional frying (10.83, 3.70, 0.59, and 1.11, respectively) indicating better quality of blended oil. Practical applications Vacuum frying employed in the present study resulted in reduced fat pear chips with retention of quality of frying medium as compared to conventional frying. This novel approach could be a feasible, economical process for food processing industries for the production of low‐fat pear chips that prolong the shelf‐life of frying medium.

Design and development of sub‐baric thermal processer for frying ofGulab jamun: A deep‐fat fried dairy product

“…Further, there was no significant change in the color of oil even after used for about 100 frying cycles for frying Gulab jamun . This could be attributed to lesser intensity of heating effect on oil components, because of vacuum/sub‐baric environment created in the design and due to non‐availably of oxygen (Juvvi et al, 2020). Similarly, during air and vacuum frying of fish skins an improvement in uniform microstructures and decrease in fat uptake recoveries (9.80% and 27.70%, respectively) has been recorded by other researchers (Mingchih, Huang, & Sung, 2021).…”

“…Sub‐baric frying (frying under vacuum) is an innovative technology that has gained acceptance in recent times for manufacture of healthy and nutritious deep fried food products. Among the various advantages reported for vacuum fried food products include better quality attributes in terms of color and texture and lower oil uptake and acrylamide content (Granda, Moreira, & Tichy, 2004; Juvvi, Kathika, & Debnath, 2020; Yamsaengsung, Yaeed, & Ophithakorn, 2017). The vacuum fried French fries contain low acrylamide content and also contain low amount of odorants.…”

Reviewing the effects of vacuum frying on frying medium and fried foods properties

“…Although the low oil content of the processed food was initially considered as an advantage of this technology, a significant oil uptake observed during the depressurisation step caused by the quick change from vacuum to atmospheric pressure has made the researchers be persistently exploring alternatives to overcome this drawback and improve the vacuum frying technology being the inclusion of microwave heating, ultrasound or their combination, before or during the process, the most investigated ones (Devi et al, 2018). According to Juvvi et al (2020), since the frying oil occupy the empty pores left by the evaporated water molecules, oil uptake and moisture loss are interdependent and occur concurrently; therefore, a faster heating will cause a faster evaporation rate and reduced oil uptake.…”

“…According to Juvvi et al . (2020), since the frying oil occupy the empty pores left by the evaporated water molecules, oil uptake and moisture loss are interdependent and occur concurrently; therefore, a faster heating will cause a faster evaporation rate and reduced oil uptake.…”

Effect of New Frying Technology on Starchy Food Quality

“…In particular, there were differences in the number and size of the stomata on the surfaces of the potato chips, which led to lower oil absorption for the vacuum-fried potato chips. Oil uptake has also been reported to be lower for vacuum-fried than conventional fried pear slices [68] and banana slices [69]. In conventional frying, the increase in the temperature of the product from the ambient temperature to the boiling point of water causes the water in the product to evaporate rapidly.…”