Colloid chemistry approach to understand the storage stability of fermented carrot juice

Application of Optical and Rheological Techniques in Quality and Storage Assessment of the Newly Developed Colloidal-Suspension Products: Yogurt-Type Bean-Based Beverages

The objectives of this study were to compare the properties of the yogurt-type bean-based beverages B and BG produced from the nongerminated and germinated beans, respectively, by high-pressure homogenization (HPH) and fermentation with three starter cultures. Optical techniques were used to evaluate the particle size distribution (PSD), color parameters, and instability during storage, while rheological tests were used to evaluate the shear viscosity, flow behavior, and viscoelastic properties. The BG compared to B, irrespective of the starter culture used, showed a higher mean diameter and Span of PSD (d_4,3 ≈ 76.8-84.2, Span ≈ 2.24-2.35 for BG vs. d_4,3 ≈ 38.2-47.0, Span ≈ 1.90-2.00 for B). The BG vs. B showed lower viscosity (0.47 Pa·s for BG vs. 0.81 Pa·s for B at shear rate 75 s^-1) and slightly lower but satisfactory stability (after 21 days at 6 °C, the Turbiscan Stability Index TSI ≈ 1.3-2.0 for BG vs. TSI ≈ 0.6-0.9 for B). Both B and BG were characterized by light-yellow color and showed the characteristics of a viscoelastic fluid. The HPH and germination mainly affected the properties of the tested plant tissue, which has a direct impact on the properties of the final products.

Physicochemical stability of pineapple suspensions: the integrated effects of enzymatic processes and homogenization by shear

The pineapple (Ananas comosus) is an important tropical fruit in the world market. Its pulp has significant nutritional value while the peel and the core, in spite of being high in dietary fibre and nutrients, are generally considered to be agro-industrial waste. The aim of this research was to evaluate the effect that the integrated enzymatic and shear homogenization processes have on the physicochemical stability of pineapple base suspensions (pulp, core, and peel extract). Initially, an enzymatic hydrolysis process was evaluated with a completely randomized factorial design. Independent variables: incubation time (t_inc) (1-4 h) and [enzyme] (0-200 ppm). Dependent variables: viscosity (μ) and particle sizes (D_[3;2] and D_[4;3]). The results showed a reduction of (μ) (70.7%), D_[3;2] (54.2%), and D_[4;3] (61.8%) for the optimized treatment (t_inc = 3.2 h and [enzyme] = 200 ppm) compared to the control (t = 0, without enzyme). The effect of the integrated enzymatic treatment with a serial homogenization process was subsequently evaluated. Independent variables: high-speed homogenization time (t₁) (15-20 min), recirculation time in high pressure homogenizer (t₂) (3-7 min), and arabic gum (AG) (0.6-1.0%). Dependent variables: total suspension solids (TS_S), zeta potential (ζ), μ, spectral stability index (R), D_[3;2], and D_[4;3]. The application of the integrated processes of enzymatic treatment and serial homogenization was more effective to be able to obtain a stable pineapple-based suspension. The experimental optimization of multiple responses defined t₁ = 16.4 min, t₂ = 7 min, AG = 0.98%, and TSs = 15.7 ± 0.5%, ζ = - 23.1 ± 0.4 mV, µ = 221 ± 11 cP, D_[3;2] = 56.8 ± 2 µm and D_[4;3] = 120.6 ± 4 µm and R = 0.58 ± 0.02 were obtained.

Nutritional composition, antioxidant activity, volatile compounds, and stability properties of sweet potato residues fermented with selected lactic acid bacteria and bifidobacteria

The effects of four kinds of lactic acid bacteria (LAB) and one bifidobacteria on nutritional composition, antioxidant activity, volatile compounds and stability properties of fermented sweet potato residues (SPR) were investigated. The soluble dietary fiber (12.92-16.63 g/100 g DW), total polyphenols content (90.51-97.35 mg/100 g DW), organic acids, and stability of SPR were increased after fermentation. The DPPH radical scavenging capacity (39.49-62.04 mg AAE/100 g DW) and ferric reducing antioxidant power (47.14-71.87 mg TE/100 g DW) were also increased, of which SPR fermented with Lacticaseibacillus rhamnosus CICC 23119 exhibited the highest values. Meanwhile, the anti-nutritional compound (oxalic acid) was decreased from 0.46 to 0.08-0.30 mg/g DW. Also, the fermented SPR exhibited different flavors compared with SPR, due to the production of acids especially antiseptic hexanoic acid and sorbic acid. Therefore, these results can provide a theoretical basis for the high-value utilization of SPR.

Probiotic fermentation modifies the structures of pectic polysaccharides from carrot pulp

Previous studies have suggested that water-soluble polysaccharides from fermented carrot pulp (WSP-p) have stronger anti-diabetic effects than those from un-fermented carrot pulp (WSP-n). This study aimed to improve understanding of these functional differences by comparing their molecular structures. Weight-average molecular weights of WSP-p fractions were lower than those of the corresponding WSP-n fractions. While both WSPs had similar functional groups, more fragmented particles were observed on the surface of large particles of WSP-n than WSP-p. Monosaccharide composition and methylation analysis confirmed that both WSP-p and WSP-n were pectic polysaccharides, containing rhamnogalacturonan-I-type polysaccharides with 1,4-linked α-d-galacturonic acid residues and homogalacturonan regions with 1,4-GalpA linkages. ¹H and ¹³C NMR showed that they had similar linkage patterns. These findings suggested that probiotic fermentation of WSP mainly cleaved the linkages between repeating units, and resulted in less polydisperse molecular size distributions.

Is overnight fresh juice drinkable? The shelf life prediction of non-industrial fresh watermelon juice based on the nutritional quality, microbial safety quality, and sensory quality

OBJECTIVE

The aim of this study was to obtain the time range of non-industrial fresh watermelon juice (FWJ), which is widely used in the catering industry under different storage conditions, with safe-drinkable quality, and the drinking time range of fresh juice with good nutritional quality and sensory quality.

METHOD

The quality of non-industrial FWJ was audited by assessing the shelf life of non-industrial FWJ through microbial safety, nutritional, and sensory quality investigating during 24 h of storage at 4, 25, and 37°C.

RESULTS

According to the microbial safety quality, the safe drinking time of FWJ was within 12, 4, and 4 h when stored at 4, 25, and 37°C, respectively. Based on the nutritional and sensory quality, FWJ was drinking with good quality within 2 h, and with just acceptable quality for no more than 4 h when stored at 4 or 25°C. Electronic nose and gas chromatography-mass spectrometry (GC-MS) could effectively distinguish and identify the changes in volatile components in FWJ under different storage conditions.

CONCLUSION

It is a feasible method to predict the shelf life of non-industrial FWJ by this method, and hence to guarantee non-industrial FWJ being drinking with safety and health, and it might be used in many other fresh juice shelf life predictions.

Effects of fermentation with Lactobacillus plantarum NCU137 on nutritional, sensory and stability properties of Coix (Coix lachryma-jobi L.) seed

This study aimed to investigate the effect of fermentation with Lactobacillus plantarum NCU137 on the nutritional, sensory and stability properties of Coix (Coix lachryma-jobi L.) seed. The nutritional compounds, including free amino acid, free fatty acid, soluble dietary fiber and organic acids of fermented coix seed were significantly (p < 0.05) increased than those of non-fermented coix seed. The fermented coix seed exhibiting a special flavor, due to the production of acids, the decreased level of aldehydes and ketones, and the increased level of alcohols in the volatile compounds, whereas the amount of hazardous substance 2-pentylfuran was reduced and natural antiseptic hexanoic acid was produced. The increased viscosity together with the larger particle size and the reduced absolute ζ potential contribute to the stability of the fermented coix seed paste system. Therefore, fermentation with L. plantarum NCU137 could improve the nutritional, sensory and stability properties of coix seed.

Fermented carrot juice attenuates type 2 diabetes by mediating gut microbiota in rats

In the present study, we aimed to investigate the therapeutic mechanisms of carrot juice fermented with Lactobacillus rhamnosus GG (LGG) on type 2 diabetic mellitus (T2DM) based on the regulation of gut microbiota. Carrot juice fermented with LGG was enriched with free phenols, organic acids and short-chain fatty acids (SCFAs). Supplementation of carrot juice fermented with LGG (DFCL) could favorably regulate blood glucose, insulin, antioxidant capacity and morphology of the pancreas and kidney in the diabetic rats, accompanied by an increase of SCFAs in the cecum. Furthermore, high-throughput sequencing (HTS) analysis revealed that DFCL supplementation altered the composition of gut microbiota, showing increased relative abundances of functionally relevant enterotypes, such as Christensenellaceae_R-7_group, Oscillibacter, Ruminococcaceae_UCG-013, Lachnospiraceae_NK4A136_group and Akkermansia. In addition, Spearman's correlation analysis revealed that Desulfovibrio, Ruminococcaceae and Alloprevotella were closely correlated with biochemical biomarkers. Meanwhile, DFCL treatment regulated the expressions of genes involved in glucose metabolism at the mRNA and protein levels.

Origin of Hypoglycemic Benefits of Probiotic-Fermented Carrot Pulp

It has been found that probiotic-fermented carrot pulp has a beneficial effect in reducing blood glucose, more so than unfermented pulp. This paper explores the reason for this by looking at fermentation-induced changes in nutritional components and hypoglycemic effects of its polysaccharides. Micronutrient content showed minor changes, except for titratable acidity. Fat and protein decreased, while total carbohydrates increased. These polysaccharides are pectinic, and the number of total polysaccharides rose after fermentation. Scanning electron microscopy showed that the morphology changed from filamentous solid to spiral. The molecular weight of water-soluble polysaccharide (WSP) diminished after fermentation, while those of acid- and alkali-soluble polysaccharides increased. WSP had stronger hydroxyl radical scavenging activity in vitro, and WSP from probiotic-fermented carrot pulps showed better hypoglycemic effects than WSP from non-fermented carrot pulps in animal experiments. Thus, the fermentation-induced improvement in diabetes control from fermented carrot pulp probably arises from its WSP.