RESUMO
The rational use of autoclaved starches in food applications is difficult because there is a lack of information on their structure-functionality relationship. The novelty of this research relies on disclosing such an association. Hylon V starch was autoclaved at 105, 120, and 135°C to investigate its crystalline and double-helical features and its relationship with functionality. In autoclaved Hylon V starch, interactions of amylopectin and amylose improved while the crystalline regions decreased. The degree of double helices (DD) decreased after autoclaving at 105°C and the degree of order (DO) increased after treatment at 120 and 135°C. The water solubility index (WSI) (4.63-6.38%) and swelling power (SP) (4.39-7.1 g/g) increased when the temperature increased. On the other hand, water (103.49-225.01%) and oil (61.91-94.53%) holding capacity (WHC and OHC, respectively) increased after autoclaving treatment, although the values decreased with the treatment intensity. The functional properties were affected when the structure changed as a function of the treatment temperatures. PCA analysis showed that WSI and SP of autoclaved Hylon V starch were associated with a high DD, with better compaction, and with stronger amylopectin-amylose interactions. WHC and OHC were associated with better crystallinity, stronger interactions of amylopectin and amylose, and heterogeneous double-helical crystallites. These findings are useful for understanding the structure-functionality relationship of autoclaved Hylon V starch and pave the way for future research regarding the effects of its incorporation on the properties of food matrices such as bread, yogurt, cakes, and pudding.
RESUMO
In this study, the resistant starch (RS) formation, crystallinity, and double helical order of autoclaved (120 °C) normal (ANS) and high amylose (AHS) corn starches retrograded at ~4-26% of water content were investigated. ANS and AHS retrograded at ~25-26% of water content were more crystalline (~35-40%) and formed by more close-packed double helices (R1000/1022 cm-1 = 1.145-1.290). The highest content of RS (38.8%) was found in AHS retrograded at 25.52% of water content meanwhile in ANS, the maximum content of RS was 6.6% at 21.60% of water content despite its structural order was increased with the increase of water content. The recrystallization of amylopectin interfered with the formation of homogeneous crystalline structures of amylose preventing the formation of retrograded RS in ANS, while in AHS, a relationship between structure and RS formation was observed, suggesting that the close-packed double helices and the proportion of homogeneous amylose crystallites increased the resistance to enzymatic digestion.