Yueh-Hao Ronny Hung, Chen-Hsun Yang, Yen-Tso Lai, Darin Khumsupan, Wei-Ting Hung, Chien-Hao Chen, Shella Permatasari Santoso, Kaemwich Jantama, Chang-Wei Hsieh, Kuan-Chen Cheng
While rice is an attractive cereal for low-alcohol beverage innovation, inefficient starch saccharification remains a production bottleneck compared to traditional barley brewing. This study developed an integrated strategy combining rice koji-driven mashing and sequential co-fermentation with Saccharomyces cerevisiae and Hanseniaspora vineae to address the above limitations and improve the quality of rice beer. Rice koji exhibited robust hydrolytic activity during the initial mashing stage (45°C), significantly changing the wort carbohydrate composition with a 2.6-fold increase in glucose concentration compared to the control. The modified sugar profile and sequential inoculation fundamentally shifted yeast population dynamics. Unlike barley-based fermentation where S. cerevisiae dominated, the rice-based wort allowed both yeasts to maintain comparable populations, likely due to lower ethanol accumulation. This microbial interaction significantly enriched volatile compounds, particularly acetate esters. Specifically, compared to the single strain fermentation, 2-phenylethyl acetate (floral note) increased from undetectable levels to 15.91 mg/L in the sequential co-fermentation group. Correspondence analysis correlated sequential co-fermentation with floral aftertaste attributes, reflecting higher sensory scores in overall acceptability for the developed rice beer. Overall, the synergy between koji-assisted enzymatic hydrolysis and yeast population modulation provides a robust pathway for enhancing the quality and aromatic complexity of rice-based beverages. © 2026 Elsevier Ltd.
Institute of Food Science and Technology, College of Bioresources and Agriculture, National Taiwan University, No. 1, Section 4, Roosevelt Rd., Taipei, 10617, Taiwan; Department of Food Science, National Taiwan Ocean University, No. 2, Pei- Ning Road, Keelung, 202301, Taiwan; Institute of Biotechnology, College of Bioresources and Agriculture, National Taiwan University, No. 1, Section 4, Roosevelt Rd., Taipei, 10617, Taiwan; Department of Food and Nutrition, Providence University, No. 200, Sec. 7, Taiwan Blvd., Shalu Dist., Taichung City, 433303, Taiwan; Department of Food and Beverage Management, National Kaohsiung University of Hospitality and Tourism, No.1, Songhe Rd., Xiaogang Dist., Kaohsiung City, 812301, Taiwan; Department of Chemical Engineering, Widya Mandala Surabaya Catholic University, Kalijudan 37, Surabaya, 60114, Indonesia; Collaborative Research Center for Sustainable and Zero Waste Industries, Kalijudan 37, East Java, Surabaya, 60114, Indonesia; Metabolic Engineering Research Unit, School of Biotechnology, Suranaree University of Technology, 111 University Avenue, Muang Nakhon Ratchasima, Suranaree, 30000, Thailand; Department of Food Science and Biotechnology, National Chung Hsing University, South Dist., Taichung City, 402, Taiwan; Department of Food Science, National Ilan University, Shennong Rd., Yilan City, 26047, Taiwan; Department of Optometry, Asia University, 500, Lioufeng Rd., Taichung, Wufeng, 41354, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, 91, Hsueh-Shih Road, Taichung, 40402, Taiwan; Department of Food Science, Fu Jen Catholic University, 510, Zhongzheng Rd., New Taipei City, 242062, Taiwan