School of Biochemistry Engineering, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2950, Valparaíso 2362803, Chile.
Molecules. 2022 Apr 30;27(9):2867. doi: 10.3390/molecules27092867.
Naringin and limonin are the two main bitter compounds of citrus products such as grapefruit juice. The aim of this investigation was to evaluate the reduction in both bitter components simultaneously using a combined biochemical and physical approach. The proposed strategy was based on the use of heterofunctional supports with glyoxyl groups that allow for the covalent immobilization of naringinase, which hydrolyses naringin and alkyl groups that allow for the adsorption of limonin. The supports were butyl-glyoxyl agarose (BGA) and octyl-glyoxyl agarose (OGA), which were characterized in terms of aldehyde group quantification and FTIR analysis. The optimal pH and temperature of free and immobilized enzymes were assessed. The maximum enzyme loading capacity of supports was analyzed. Debittering of grapefruit juice was evaluated using soluble enzyme, enzyme-free supports, and immobilized catalysts. Enzyme immobilized in BGA reduced naringin and limonin concentrations by 54 and 100%, respectively, while the use of catalyst immobilized in OGA allowed a reduction of 74 and 76%, respectively, obtaining a final concentration of both bitter components under their detection threshold. The use of OGA biocatalyst presented better results than when soluble enzyme or enzyme-free support was utilized. Biocatalyst was successfully applied in juice debittering in five repeated batches.
柚皮苷和柠檬苦素是葡萄柚汁等柑橘类产品中的两种主要苦味化合物。本研究旨在采用生化和物理相结合的方法同时降低这两种苦味成分。该策略基于使用带有乙二醛基的杂化功能载体，允许固定化柚皮苷酶，该酶水解柚皮苷，同时使用带有烷基的载体吸附柠檬苦素。所用的载体为丁基乙二醛琼脂糖（BGA）和辛基乙二醛琼脂糖（OGA），并对其醛基定量和傅里叶变换红外（FTIR）分析进行了表征。评估了游离酶和固定化酶的最佳 pH 值和温度。分析了载体的最大酶载量。采用游离酶、无酶载体和固定化催化剂对葡萄柚汁进行脱苦评估。固定在 BGA 中的酶可分别将柚皮苷和柠檬苦素的浓度降低 54%和 100%，而使用固定在 OGA 上的催化剂可分别降低 74%和 76%，使两种苦味成分的终浓度均低于检测阈值。与使用游离酶或无酶载体相比，OGA 生物催化剂的使用效果更好。该生物催化剂在五次重复批次的果汁脱苦中得到了成功应用。
