Spinei Mariana, Oroian Mircea
Department of Food Technologies, Food Production and Environment Safety, Faculty of Food Engineering, Stefan cel Mare University of Suceava, 720229 Suceava, Romania.
Polymers (Basel). 2022 Mar 28;14(7):1378. doi: 10.3390/polym14071378.
Grape pomace is one of the most abundant by-products generated from the wine industry. This by-product is a complex substrate consisted of polysaccharides, proanthocyanidins, acid pectic substances, structural proteins, lignin, and polyphenols. In an effort to valorize this material, the present study focused on the influence of extraction conditions on the yield and physico-chemical parameters of pectin. The following conditions, such as grape pomace variety (Fetească Neagră and Rară Neagră), acid type (citric, sulfuric, and nitric), particle size intervals (<125 µm, ≥125−<200 µm and ≥200−<300 µm), temperature (70, 80 and 90 °C), pH (1, 2 and 3), and extraction time (1, 2, and 3 h) were established in order to optimize the extraction of pectin. The results showed that acid type, particle size intervals, temperature, time, and pH had a significant influence on the yield and physico-chemical parameters of pectin extracted from grape pomace. According to the obtained results, the highest yield, galacturonic acid content, degree of esterification, methoxyl content, molecular, and equivalent weight of pectin were acquired for the extraction with citric acid at pH 2, particle size interval of ≥125−<200 µm, and temperature of 90 °C for 3 h. FT-IR analysis confirmed the presence of functional groups in the fingerprint region of identification for polysaccharide in the extracted pectin.
葡萄皮渣是葡萄酒行业产生的最丰富的副产品之一。这种副产品是一种复杂的底物，由多糖、原花青素、酸性果胶物质、结构蛋白、木质素和多酚组成。为了使这种材料具有价值，本研究重点关注提取条件对果胶产量和理化参数的影响。确定了以下条件，如葡萄皮渣品种（黑菲特斯卡和黑拉腊）、酸的类型（柠檬酸、硫酸和硝酸）、粒度区间（<125 µm、≥125−<200 µm和≥200−<300 µm）、温度（70、80和90°C）、pH值（1、2和3）以及提取时间（1、2和3小时），以优化果胶的提取。结果表明，酸的类型、粒度区间、温度、时间和pH值对从葡萄皮渣中提取的果胶的产量和理化参数有显著影响。根据所得结果，在pH值为2、粒度区间为≥125−<200 µm、温度为90°C、提取3小时的条件下，用柠檬酸提取得到的果胶产量、半乳糖醛酸含量、酯化度、甲氧基含量、分子量和当量最高。傅里叶变换红外光谱（FT-IR）分析证实了提取的果胶中多糖鉴定指纹区域存在官能团。
