Germination and fermentation synergistically tailor the starch structure within brown rice and the quality features of brown rice tea

Abstract

Notwithstanding brown rice (BR) has recently evoked extensive exploration owing to its rich nutrients and exceptional health benefits, it remains largely unclear how germination combined with fermentation (GCF) impact the starch structure within BR as well as the quality features of BR-based products. Here, the BR samples under different inoculum sizes (0.4-4 %) were used. Generally, the hydrolysis of the starch amorphous regions and crystalline regions during GCF decreased the short-range order structure of starch molecules; however, the degradation of amorphous starch and the reassembly of amylopectin induced by the microorganism hydrolyzation could result in increased structural order of starch when 1 % inoculum size was achieved. Additionally, GCF treatment with 1 % inoculum size imparted the brown rice tea (BRT) with acceptable sensory and nutritional properties, the BRT exhibited the highest levels of reducing sugar (1435.01 mg/kg) and soluble protein (235.14 mg/kg).

Keywords: Brown rice; Fermentation; Germination; Molecular structure; Starch.