The addition of oat at varying percentages (26%, 32%, 38%, 44% and 50%) was used to evaluate the structural, microstructural, and physicochemical changes in instant-extruded rice (IER). A mixture of broken rice and oat flour was extruded in a twin-screw extruder. It was found that when adding 44% oats, the gelatinization degree of the mixed powder was the lowest (89.086 ± 1.966%). The dietary fiber content increased correspondingly with the increase in oat addition. Analyses of texture properties revealed that the hardness, adhesive, and resilience values increased and then decreased with oat addition. Compared with other common instant rice (IR), the advantages of IER were evaluated in terms of microstructure, digestive performance, and flavor. IER with 44% oat addition obtained in this study had higher hardness, adhesiveness, rehydration time, and sensory score, and the content of resistant starch (RS) reached 6.06%. The electronic nose and electronic tongue analyses could distinguish the flavor of different IR efficiently. This study showed the feasibility of preparing fiber-enriched IER. The results demonstrated the potential for the development and utilization of broken rice, providing a reference for the development of IER.

Drying is a widely utilized method for extending the shelf life of food products. This study applied four drying techniques—natural air drying (NAD), hot air drying (HAD), microwave drying (MD), and vacuum freeze drying (VFD)—to dehydrate water bamboo shoots (WBS), and investigated their effects on the quality and volatile organic compound (VOC) profiles of the dried WBS. The results showed that MD achieved the fastest drying rate, whereas NAD exhibited the slowest. Both MD and VFD samples possessed porous structures. However, the VFD-treated samples retained the highest levels of Vitamin C (VC) and total phenols, and showed the least color deviation compared to the fresh samples, which was closely associated with its low-temperature and vacuum processing conditions. A total of 52 VOCs were identified in this study. Among them, 3-methyl-butanal and 5-methyl-2-furfural were the most abundant VOCs in the treated samples. 3-methybutanal, pentanal, butanal, and 5-methyl-2-furfural were identified as the characteristic VOC markers for the HAD, NAD, VFD, and MD groups, respectively. In conclusion, this study determined that VFD effectively maintained the drying quality of WBS, with butanal identified as its characteristic VOC organic compound. These findings provide valuable insights for the practical production of high-quality dried WBS.

Rice has excellent nutritional quality as a dietary food and is easily puffed. The aim of this study was to investigate the effects of puffing technology on the physicochemical parameters, structure properties and volatile components of brown rice (BR) and refined rice (RR). XRD and FT-IR spectroscopic data demonstrated that puffing under high temperature and pressure conditions triggered starch gelatinization, concurrently reducing starch crystallinity and inducing a V-type polymorphic structure. In addition, it substantially weakened hydrogen bonding networks in rice flour. In detail, 136 volatile compounds of raw and puffed rice were analyzed by HS-SPME-GC-MS, and the results showed that aldehydes, ketones, and pyrazines were the main volatile aroma compounds after puffing. By correlation analysis, benzaldehyde, 2-octenal, 2-methoxy-phenol, and furfural were identified as key contributors. The volatile components, especially ketones and alcohols, were higher in the BR as compared to those in the RR, with a significant difference observed between the two (p < 0.05). Combined with sensory evaluation, 1212CH was found to have a high score (17.63). These results could provide a theoretical basis for understanding the effect of puffing on rice flour and the volatile components of puffed products.