熟化枸杞子的加工工艺及功能特性

为了有效开发利用枸杞子资源,进一步提高枸杞子附加值,该文以新鲜枸杞子为原料,在传统干制工艺的基础上,基于美拉德反应原理,开发熟化枸杞子新产品,并对其活性进行检测。研究结果表明,熟化枸杞子三段式干制工艺为:干制预处理阶段温度为60℃,时间为12 h;熟化阶段温度为80℃,时间为24 h,相对湿度65%;定型阶段温度45℃,干制6 h即可。制备的熟化枸杞子为黑褐色、酸甜适口、抗氧化活性显著高于(P0.05)普通干制枸杞子,其总还原能力、羟自由基清除能力、DPPH自由基清除能力分别是普通干制枸杞子的1.87倍、1.45倍和2.21倍,是一种较好的抗氧化食品,枸杞子的附加值得到了有效提高,并且该熟化枸杞子的制备工艺简单、成果易转化,具有很好的应用前景。

Processing technology and functionality of cooked fruits of Lycium Barbarum L.

Lycium barbarum L., which is well known as one of the traditional Chinese medicines, is mainly cultivated in Northwest China. Due to its delicious taste and nutritional value, its consumption demands are increasing tremendously worldwide. It brings great economic benefit for the local community. ButLycium barbarumL. is highly perishable, which makes it have a short storage period. And driedLycium barbarumL. becomes a core product ofLycium barbarum L.. However, single product is difficult to satisfy the demands of modern consumers. In order to increase the variety ofLycium barbarumL. products and further promote the profitability of Lycium barbarumL., a new processing technology ofLycium barbarum L. suitable for industrial production was developed and optimized in this study. The processing technology was mainly based on the Maillard reaction principle. High temperature and high humidity conditions were 2 key parameters of the processing technology. During the processing, freshLycium barbarum L. was processed into black cookedLycium barbarum L. in high temperature and high humidity conditions. The processing technology was composed of 3 stages: The pre-dewatering treatment stage, the cooking treatment stage and the final forming treatment stage. First,Lycium barbarum L. was dried at 4 different temperatures (50, 55, 60 and 65℃) at the first stage. The effects of temperature and drying time on moisture content and damage rate ofLycium barbarum L. were evaluated comprehensively. Then,theLycium barbarum L. after pre-dewatering treatment was cooked under constant temperature of 65, 70 and 80℃ and relative humidity of 65%. And the product quality was evaluated through reducing sugar content, amino acid nitrogen content and color of cooked Lycium barbarum L.. At last, the cooked Lycium barbarum L. was dried at 45℃ respectively for 4, 6 and 8 h in order to gain the product with the best sensory quality. Experimental results under the first stage showed that the drying temperature should not be too high. High drying temperature would lead to higher damage rate ofLycium barbarum L.. In contrast, the temperature should be higher at the cooking treatment stage. High temperature was benefit to Maillard reaction. Through researching, the three-phase-drying method for the cookedLycium barbarum L. was found. The temperatures for the pre-dewatering treatment, the cooking treatment and the final forming treatment were 60, 80 and 45℃, respectively. The processing time was 12, 24 and 6 h, respectively. And the humidity of the cooking treatment stage should be held within 65%. The cookedLycium barbarum L. had a color from red to black brown and a sweet and sour taste. And its antioxidant activity was better than the normal dried Lycium barbarum. The reducing power, and ·OH and DPPH (1,1-diphenyl-2-picryl-hydrazyl) radical scavenging activities of the cookedLycium barbarum L. were about 1.87, 1.45 and 2.21 times that of the normal dried production. The study provides a valuable and useful method for the development and utilization ofLycium barbarum L..