酸枣酶解液热反应制备食用香料工艺优化

Optimization of the heating reaction for preparing edible flavor from jujube enzymatic hydrolysate

摘要:

为了制备酸枣特色香气风格的食用香料,本研究采用酸枣酶解液与葡萄糖焦糖化料液热反应的方法制备香料,首先以还原糖和氨基酸的含量变化量为指标,通过单因素实验研究复合酶浓度、酶解温度、酶解时间对酸枣果肉的酶解效果,然后将酶解后的酸枣果肉水提液进行浓缩,再与葡萄糖焦糖化料液混合进行热反应,利用单因素实验和响应面实验以感官评价为指标来探索反应时间、反应温度、初始pH、料液比(浓缩液:焦糖化料液)对香料样品品质的影响,并测定了产物的褐变值、挥发性成分以及抑菌性和抗氧化性。研究结果表明,酸枣果肉最佳酶解条件为：复合酶浓度0.28%(果胶酶∶纤维素酶∶木瓜蛋白酶=1∶1∶2m/m),酶解时间4.0 h,酶解温度45℃。样品的A420值(褐变值)随反应时间、反应温度、初始pH的升高而升高,随浓缩液与葡萄糖焦糖化料比值的升高,先降低后稍有上升,且A420与感官评分结果无直接关系。响应面实验得到最佳热反应工艺为：浓缩液与焦糖化料液比例3.1,反应时间58min,反应温度139℃,初始pH 6.0,在该条件下制备的香料感官评分较好。所检测到的挥发性成分中糠醛、糠醇、5-甲基呋喃醛、5-甲基-2-呋喃甲醇等物质具有焦香、甜香等香味,可以给酸枣香料带来的独特的风味。抑菌性和抗氧化实验结果表明,酸枣香料具有抗氧化性和抑菌性,本研究可为酸枣香料的开发和应用及酸枣高值化利用提供理论支持。

Abstract:

In order to prepare edible flavor with aroma style of sour jujube, this study used Sour jujube enzymatic hydrolysate and then added glucose caramelized material for thermal reaction. Firstly, with the content change of reducing sugar and amino acid as the index, single factor method was employed to investigate the effects of complex enzyme concentration, enzymolysis temperature, and enzymolysis time on the enzymolysis of sour jujube flesh. Then, the enzymolysis water extract of jujube flesh was concentrated, and mixed it with glucose caramelized material for thermal reaction. Use single factor method and response surface design to explore the effects of reaction time, reaction temperature, initial pH, and material liquid ratio on the flavor sample quality using sensory evaluation as indicators. The browning value, volatile components, antibacterial and antioxidant properties of the product were determined. The results showed that the optimal enzymolysis conditions of jujube pulp were as follows: the concentration of complex enzyme was 0.28%, the enzymolysis time was 4.0 h, and the enzymolysis temperature was 45 ℃.The A420 value (browning value) of the sample increases with the increase of reaction time, reaction temperature, and initial pH. It first decreases and then slightly increases with the increase of the ratio of concentrated solution to glucose caramelized material, and A420 is not directly related to the sensory score results. The optimal preparation condition for sour jujube flavor was: the ratio of concentrated solution to caramelized feed solution 3.1, the reaction time 58 minutes, the reaction temperature 139 ℃, and the initial pH 6.0. The flavor prepared under this condition had a good sensory score, and the volatile components detected including furfural, furfuryl alcohol, 5-methylfuranal, 5-methyl-2-furanmethanol, with a burnt and sweet aroma, which can bring a unique flavor to the sour jujube flavor. This study can provide theoretical support for the development and application of sour jujube flavor and the high-value utilization of sour jujube.