Starch concentration is an important factor for controlling its digestibility during hot-extrusion 3D printing.

Controlling the digestibility of starch by Hot-extrusion 3D printing (HE-3DP) is a new way to achieve personalized customization of starch-based foods. In this study, structural changes and in vitro digestibility of rice, wheat and potato starch gel materials at different concentrations during hot-extrusion 3D printing (HE-3DP) were studied, and their relationship was clarified. The results showed that increasing concentration of starch gel material could effectively resist the disruption of the ordered structure by hydrothermal and shear and then promoted the rearrangements of starch molecular chain. Interestingly, the newly formed ordered structure led to a significant increase in slowly digestible starch (SDS)+ resistant starch (RS) content of rice, wheat and potato starch-based printing samples at 25 % concentration, reaching 29.59%, 28.43% and 48.82%, respectively. Overall, starch concentration was found an important factor in regulating the ordered structure of printed samples and controlling its anti-digestibility during HE-3DP.

Development changes in multi-scale structure and functional properties of waxy corn starch at different stages of kernel growth.

Waxy corn starch is widely used in food and papermaking industries due to its unique properties. In this work, the structural and functional properties of starch isolated from waxy corn at different stages of kernel growth were investigated and their relationships were clarified. The results showed that with kernel growth, the surface of starch granules became smooth gradually, and the inner growth rings and the porous structure grew and became clear. Meanwhile, the weight-average molecular mass (Mw), root mean square radius (Rg), and average particle size increased while the amylose content decreased, which should account for the decreased pasting temperature (from 71.37 to 67.44 °C) and increased peak viscosity (1574.2 to 1883.1 cp) and breakdown value observed. Besides, the contents of slowly digestible starch (SDS) and resistant starch (RS) in waxy corn starch decreased significantly (from 44.01% to 40.88% and from 16.73% to 9.80%, respectively, p < 0.05) due to decreases in the double helix content, crystallinity, and structural order, and increases in the semi-crystalline lamellae thickness and the amorphous content. This research provides basic data for the rational utilization of waxy corn starch at different stages of kernel growth.

Understanding the nutritional functions of thermally-processed whole grain highland barley in vitro and in vivo.

The objective of this study was to investigate the nutritional functions of highland barley subjected to heat-moisture treatment (HMT) and dry heat treatment (DHT) in vitro and in vivo. In vitro test indicated HMT and DHT play part in the reduced glycemic potency of highland barley. Meanwhile, in vivo results showed that thermally-processed highland barley (THB) supplementation significantly decreased the body weight and serum glucose, improved oxidation resistance and altered the composition of gut microbiota. Bifidobacteria, Fusicatenibacter and Desulfovibrio were identified as types of bacteria that might related to the relatively higher content of dietary fiber in THB. The Spearman's correlation analysis revealed that Fusicatenibacter and Desulfovibrio were positively correlated with T-AOC levels. In addition, the putative metagenomes implicated that THB might regulate the metabolic pathways of gut microbiota. Overall, our findings provide important information for the rational design of highland barley-based health-promoting foods with nutritional functions.