Effect of sorbitol on the in vitro starch digestibility in semi-dried black highland barley noodles

Sorbitol is commonly used in semi-dried noodles for holding water, thus extending the shelf life. This research analyzed the effect of sorbitol on the in vitro starch digestibility in semi-dried black highland barley noodles (SBHBN). In vitro starch digestion revealed that the hydrolysis extent and digestive rate decreased with increasing sorbitol addition, although its inhibition abated when added >2 %. Compared with the control, adding 2 % of sorbitol lowered the equilibrium hydrolysis (C_∞) significantly (P < 0.05) from 75.18 to 66.57 % and decreased the kinetic coefficient (k) significantly (P < 0.05) by 20.29 %. Adding sorbitol increased the tightness of microstructure, relative crystallinity, V-type crystal, molecular structure order, and hydrogen bond strength of starch in cooked SBHBN. Meanwhile, gelatinization enthalpy change (ΔH) of starch in raw SBHBN was increased by adding sorbitol. In addition, the swelling power and amylose leaching in SBHBN added with sorbitol were reduced. Pearson correlations analysis observed significant (P < 0.05) correlations among short-range ordered structure, ΔH, and related in vitro starch digestion indexes of SBHBN after being added with sorbitol. These results revealed that sorbitol might form hydrogen bonds with starch, making it a potential additive to lower the eGI in starchy foods.

Physicochemical Effects of Lactobacillus plantarum and Lactobacillus casei Cocultures on Soy-Wheat Flour Dough Fermentation

In contemporary food production, an important role is given to the increase in the nutritional quality of foodstuff. In the bakery industry, one of the main cereals used is wheat flour (WF), which creates bread with proper sensory evaluation but is nutritionally poor. Soy-flour (SF) has increased nutrient content, and its consumption is recommended due to several health benefits. Dough fermentation with lactic acid bacteria (LAB) increases bread shelf life, improves flavor, and its nutritional quality, mostly due to its high organic acid production capability. In the present study, the addition of SF to WF, through fermentation with the cocultures of Lactobacillus plantarum and Lactobacillus casei was analyzed. Three different batches were performed by using WF supplemented with SF, as follows: batch A consisting of 90% WF and 10% SF; batch B—95% WF and 5% SF; batch C—100% WF. The fermentation with these two LABs presented several positive effects, which, together with increased SF content, improved the dough’s rheological and physicochemical characteristics. The dynamic rheological analysis exhibited a more stable elastic-like behavior in doughs supplemented with SF (G′ 4936.2 ± 12.7, and G″ 2338.4 ± 9.1). Organic acid production changes were the most significant, especially for the lactic, citric, and tartaric content.

Inhibitory effects of sorbitol on the collapse and deterioration of gluten network in fresh noodles during storage

In this paper, the inhibitory effects of sorbitol on the collapse of gluten network and textural deterioration of fresh noodles during storage were investigated, based on the changes in macroscopic and microscopic characteristics of gluten protein. Appropriate addition (≤2%) of sorbitol increased dough viscoelasticity and extension energy. Sorbitol significantly inhibited the increase of cooking loss and adhesiveness of fresh noodles, and the decrease of hardness, springiness, LA-SRC value, and GMP weight during storage. SEM images showed that sorbitol retarded the deterioration of gluten network, with maintained continuous and ordered structure after 48 h. Sorbitol enhanced the hydrogen bond interactions in gluten system and promoted dynamic depolymerization and repolymerization of gluten protein molecules during processing and cooking, this may induce the texture stability. Sorbitol as a low-molecular polyol can inhibit the deterioration in gluten network and fresh noodle texture during storage, although showing no influence on the growth of microorganisms.