Sruthi N U, Rao Pavuluri Srinivasa, Bennett Sarita Jane, Bhattarai Rewati Raman
School of Molecular and Life Sciences, Faculty of Science and Engineering, Curtin University, Bentley 6102, Australia.
Agricultural and Food Engineering Department, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
Foods. 2023 Jan 9;12(2):306. doi: 10.3390/foods12020306.
Sorghum is one of the major grains produced worldwide for food and fodder, owing to its nutritional profile advantages. However, the utilisation of whole grain sorghum as an ingredient in conventional food formulations is limited due to its poor digestibility, which requires the removal of the outer fibrous layers. Grain breakage and loss of essential nutrients also disadvantage traditional milling practices. Using carbohydrate degrading enzymes to hydrolyse the grain pericarp is a novel approach to biopolishing, where selective degradation of the pericarp layers occurs without adversely affecting the nutrient profile. A collective synergism of enzymes has been proven to cause effective hydrolysis compared to individual enzymes due to the complex presence of non-starch polysaccharides in the grain's outer layers, which comprise a variety of sugars that show specific degradation with respect to each enzyme. The present study aimed to formulate such an enzyme cocktail with xylanase, cellulase, and pectinase in different proportions for hydrolysing sorghum grain pericarp by determining the yield of specific sugars in the pericarp extract after a certain period of incubation. The results showed that the xylanase enzyme has a major effect on the grain bran composition compared to cellulase and pectinase; however, a synergistic mixture yielded more hydrolysed sugars and anti-nutrients in the extract compared to each of the enzymes individually. The results were confirmed by morphological and crystallinity studies of the soaked grain. Compared to conventional water-soaked samples, grains soaked in a cocktail with 66.7% xylanase, 16.7% cellulase, and 16.7% pectinase had visibly thinner and more degraded fibre layers.
高粱是全球生产的主要谷物之一，用于食品和饲料，这得益于其营养成分优势。然而，由于其消化性差，全谷物高粱在传统食品配方中的应用受到限制，这就需要去除外层纤维层。谷物破碎和必需营养素的损失也不利于传统的碾磨工艺。使用碳水化合物降解酶水解谷物果皮是一种生物抛光的新方法，即果皮层发生选择性降解而不会对营养成分产生不利影响。由于谷物外层中存在复杂的非淀粉多糖，其包含多种糖类，每种酶对其都有特定的降解作用，因此已证明酶的协同作用比单独的酶能更有效地引起水解。本研究旨在通过确定一定孵育时间后果皮提取物中特定糖类的产量，以不同比例配制含有木聚糖酶、纤维素酶和果胶酶的酶混合物，用于水解高粱谷物果皮。结果表明，与纤维素酶和果胶酶相比，木聚糖酶对谷物麸皮成分的影响更大；然而，与单独使用每种酶相比，协同混合物在提取物中产生了更多的水解糖和抗营养物质。浸泡谷物的形态学和结晶度研究证实了该结果。与传统的水浸泡样品相比，浸泡在含有66.7%木聚糖酶、16.7%纤维素酶和16.7%果胶酶的混合物中的谷物，其纤维层明显更薄且降解程度更高。
