Performance of technological and microbiological quality characteristics of germinated rice: a comparative study of cooking techniques

Abstract

Germination is a process used to improve the nutritional and sensory quality of brown rice, but technological and microbiological characteristics under different cooking techniques and storage conditions are neglected. In this scenario, this study aimed to evaluate the effect of rice types (germinated, parboiled and polished) on the physical, chemical and microbiological characteristics in terms of different cooking rice preparation methods and storage conditions. In general, germination did not affect crystallinity and DSC parameters but was effective in reducing the cooking time (31–22 min) using a conventional pan. A resistant starch content was observed after 30 days under freezing and increasing pronouncedly if samples were cooked in an electric rice cooker (100 %), highlighting the prebiotic aspect. After cooking (t = 0 h), germination induced the highest values of hardness (19.7 N) and chewiness (24.6 N) in germinated brown rice prepared by electric cooker. The freeze-thaw cycling (t = 30 days) reduced hardness (19.2 −12.7 N) and chewiness (17.1–5.3 N) compared to commercial and non-germinated samples (p < 0.05). Solely germinated rice stored at room temperature (25 °C) showed B. cereus growing. It is concluded that germination has the potential to become an innovative process to improve gamma-aminobutyric acid (GABA), changing the carbohydrate chemistry and texture, adding value to brown rice. In contrast, germination can favor the B. cereus growing under specific conditions and refrigeration or freezing immediately cooking consist in safe procedures to prevent outbreaks related to germinated rice-based product consumption.