Investigation of Functional and Structural Properties of Insoluble Dietary Fiber From Sichuan Natural Fermented Pickles With Different Salting Treatments

Abstract

In this study, the functional and structural properties of insoluble dietary fibers (IDFs) from Sichuan natural fermented pickle vegetables, subjected to different saline treatments are investigated. The IDF is extracted using an ultrasonic‐assisted enzyme method. The primary measurable indicators that are determined, include the water‐ and oil‐holding capacity, swelling capacity, heavy metal adsorption capacity, bile acid salts adsorption capacity, antioxidant activity, and polyphenol content. Additionally, a structural analysis is also performed using infrared spectroscopy, thermogravimetry (TG), and scanning electron microscopy. Experimental results demonstrate that both high and low salt saline fermentations have no significant effect on the techno‐functional properties of IDF in vegetables (p > 0.05); however, the physio‐functional properties, including bile acid salts adsorption capacity, heavy metal adsorption capacity (Pb, As), and the antioxidant capacity are shown to be significantly enhanced (p < 0.05). The low salt saline fermentation is shown to have an improvement effect as compared to the high salt fermentation, which is further supported by the structural characterizations including the structure and chemical groups differences, morphological changes of particles, and thermal stability differences. The findings from this work reveal the effects of saline treatments on the functional properties of IDFs, which are extracted from Sichuan pickle vegetables. In addition, they provide a potential manufacturing technique to improve the quality of the DF in Sichuan pickle vegetables.