Optimization of the extraction process of goji berry pectin using response surface methodology and its suitability as thickener for yogurt

Although goji berry with many main biological activity components is a nutritional medicinal and edible plan and widespread in the northeast of China, its current development also faces a new challenge of overcapacity. So this study was largely focused to investigate the optimal extraction process conditions (extraction water proportion, acidic pH regulating reagent, adjusted pH, extraction temperature, extraction time) for goji berry with increased yield. Box Behnken experimental design (BBD) was used to model the mathematical model of the relationship between the three main influence of pivotal extraction parameters (extraction pH, extraction time and extraction temperature) selected by the single factor experiments on the responses of goji berry pectin yield (%). Morover the predicted models were adequately fitted to the real experimental data (18.507 % ± 0.275 %, P < 0.001) for all the response variables within a short time. The maximum yield of pectin was sufficiently obtained with optimal conditions of the best water-goji ratio of 20:1, extraction pH of 2.2 adjusted by hydrochloric acid, extraction time of 80 min at 76 °C. Interesting, as thickener, goji berry pectin does not only improve the health benefits of yogurt in some studies have reported, but it also improves its sensory properties and viscosity of the yogurt in this paper. It will effectively improve the efficiency of obtaining goji berry pectin, which will provide strong experimental evidence for the widespread application of goji berry pectin. Although goji berry pectin does not have significant advantages in sensory evaluation and yogurt viscosity, it has been proven in some studies to have good functionality in terms of nutrition. This provides a good idea for the development of functional foods urgently needed in the current aging society. Goji berry will be an effective alternative source of pectin on health food industry on large scale. In addition, this paper also provides a feasible approach to effectively solve the problem of goji berry overcapacity.