Abstract: The effects of two pretreatment methods, freezing and coating, on the oil-absorption characteristics of low-temperature deep-fried reconstituted French fries were investigated. The combination of freezing pretreatment at - 24℃ for 3h had the best freezing effect. Three coating agents, SA, SPI and CMC, were screened, and 3% concentration of SA was found to be the best. On this basis, the combined freezing and coating treatment of reconstituted fries was considered to explore the above pretreatment methods on the mechanism of oil absorption of reconstituted fries and find the ?optimal preprocessing combination. The results show that: freezing pretreatment could reduce the internal moisture content of the samples and change the moisture distribution, and there was a positive correlation between the moisture content before deep - frying and the oil content after deep - frying; the oil mass fractions of the remade French fries with freezing, coating, and the combination of freezing and coating treatments were decreased by 35.02%, 10.49%, 44.83%, and 10.49%, respectively, 10.49%, 44.83% (p < 0.05); the surface as well as internal oil content of the reconstituted French fries after the combined treatment of freezing and SA coating was the lowest; CLSMshowed that the samples treated with freezing and coating had the smallest area of complex formation; SEM results showed that the samples co - treated with freezing and SA coating had the smallest number of surface crevices and low surface roughness; and the texture determination showed that coating significantly increased the hardness and brittleness of the samples. In conclusion, pretreatment could change the moisture content, distribution, surface microstructure and starch characteristics of the reconstituted fries, inhibit oil absorption and enhance the crispiness, and the combined treatment of freezing and coating had the best effect. Combined with the sensory evaluation, the combination of freezing and SA coating was the best pretreatment method for low-temperature deep-fried reconstituted French fries.

Key words: reconstituted French fries, oil content, coating agent, low temperature frying, mechanism study