Deep-fat fried battered snacks prepared using super heated steam (SHS): Crispness and low oil content

Abstract

The suitability of using super heated steam (SHS) as an alternative to pre-frying in oil, to decrease the oil content of deep-fried battered foods while obtaining crispy crusts, is shown in this manuscript. Pre-treatment of the batters in SHS for 1, 2 and 3min was compared to pre-frying with oil for 1min. All samples were final fried with oil for 3min. SHS gave slower water evaporation and the products after this pre-treatment had a rather pale colour as compared to pre-frying in oil. However, after final frying samples with similar colours were obtained after all treatments. The use of SHS allowed reducing the oil content of the crusts after final frying and the oil stayed more at the surface compared to only oil frying (1min oil pre-frying and 3min final-frying). This is probably due to a higher extent of starch gelatinization in the surface of the crust as shown using microscopy. After final frying, the combination of 3min SHS and 3min final frying in oil reduced both the oil and the moisture content of the crust compared to only oil frying. The number of sound pulses produced during fracturing of the crust and their intensity were used as values for crispness. The combination of 3min SHS and 3min final oil frying gave higher values for these sound characteristics and resulted thus in the crispier crust measured 1min after final frying. Crispness retention was studied by analyzing the sound 20min after final frying. After 20min, the combination of 2 or 3min SHS and 3min final frying in oil gave samples with the same sound intensity than pre-frying in oil, but with lower oil content.Pre-treatment in SHS for 3min instead of 1min pre-frying with oil is recommended to produce deep-fried crusts with high initial crispness and crispness retention and with low oil content.