Microstructural and dynamic oscillatory aspects of yogurt as influenced by hydrolysed guar gum

Effects of hydrocolloids and oleogel on techno-functional properties of dairy foods

This paper aims to overview the influence of different gels that including hydrocolloids and oleogel on techno-functional changes of dairy foods. The hydrocolloids are widely added to dairy products as stabilizers, emulsifiers, and gelling agents to enhance their texture, or improve sensory properties to meet consumer needs; and the newly developed oleogel, which despite less discussed in dairy foods, this article lists its application in different dairy products. The properties of different hydrocolloids were explained in detail, meanwhile, some common hydrocolloids such as pectin, sodium alginate, carrageenan along with the interaction between gel and proteins on techno-functional properties of dairy products were mainly discussed. What's more, the composition of oleogel and its influence on dairy foods were briefly summarized. The key issues have been revealed that the use of both hydrocolloids and oleogel has great potential to be the future trend to improve the quality of dairy foods effectively.

In situ exopolysaccharides from Lactobacillus helveticus MB2-1 in Sayram ketteki yoghurt: Set yoghurts properties and interactions with sodium caseinate

The effects of high exopolysaccharides (EPS) - producing Lactobacillus helveticus MB2-1 on the structure and storage stability of set yoghurts, and the interactions between its EPS (molecular weight 9.34 × 10⁴ Da) from Sayram ketteki yoghurt (SKY) and sodium caseinate (CAS) were studied. The rheology, microstructure, texture and storage stability of the three set yoghurts including control yoghurt (Control), adding-probiotic yoghurt (APY) and SKY were investigated, which showed that the SKY exhibited less shear thinning than the Control and APY, and the textural indexes and storage stability of the SKY were significantly better than that of other two yoghurts (p < 0.05). Moreover, the increased turbidity, decreased ζ potential and surface hydrophobicity of EPS/CAS complex coacervation were determined at EPS/CAS mass ratio of 3 (corresponding to 0.33 g/L of CAS and 1 g/L of EPS), mainly owing to the electrostatic attraction of the two biopolymers to form aggregates. Besides, the higher sizes and more aggregation of EPS/CAS complexes were formed at pH 3.5. Taken together, the results indicated that the high EPS-producing characteristic of L. helveticus MB2-1 could positively influence the qualities of set yoghurts, and the EPS/CAS complex coacervation in dairy products was closely related to the EPS/CAS mass ratio and pH condition.

Effect of galactomannan addition on rheological, physicochemical, and microbial properties of cultured sour cream

Sour cream is a popular fermented dairy product and galactomannans are widely used in the food industry to improve texture and stability. In this study, it was investigated the effects of different galactomannans (guar gum (GG), locust bean gum (LBG), and GG/LBG) on the rheological, physicochemical, and microbial properties of sour creams. All the sour cream samples had similar pHs (4.55-4.57), acidity (0.83-0.86%), and lactic acid bacteria viable counts (8.08-8.15 log CFU/g) after fermentation. The rheological parameters (η_a,50, K, G', G″, and tan δ) of the sour creams increased after the addition of galactomannans. The sour cream with GG showed higher η_a,50, K, G', and G″ values than the sour cream with LBG. Furthermore, the combination of galactomannans (GG/LBG) did not have any synergistic effect on the sour cream. The water-holding capacity of sour creams was enhanced by the addition of galactomannans, resulting in reduced syneresis.

Effect of adding Aloe vera jell on the quality and sensory properties of yogurt

This study was planned to investigate the effect of replacing milk fat with aloe vera gel addition on yogurt quality. Purposely, yogurt was prepared with different concentration of aloe vera gel and coded as AGY0, = Control (3.5% fat and no AG), AGY1 = (1% fat and 1% AG), AGY2 = (1% fat and 2% AG), AGY3 = (1% fat and 3% AG), AGY4 = (2% fat and 1% AG), AGY5 = (2% fat and 2% AG), and AGY6 = (2% fat and 3% AG). Aloe vera gel yogurt was analyzed for physicochemical, microbial, and sensory characteristics with defined interval (0, 7th, 14th, and 21st) days. All attributes of the yogurt were significantly (0.05) affected by the addition of aloe vera gel. Results showed that the pH (4.6-4.05), viscosity (46.4-4.3), WHC (32.8%-26.1%), fat (0.9%-3.48%), protein (3.14%-3.36%), lactose (4.07%-4.23%), ash (0.48%-0.63%), total solids (11.08%-17.18%), SNF (7.69-l5.21%), and TPC (2.36 × 107 to 1.02 × 107 CFU/ml) values of yogurt samples decreased with storage time. However, acidity and syneresis of yogurt increased with the passage of time ranging from 1.12%-1.67% and 0.9-5 ml, respectively. In conclusion, aloe vera improved the texture of the yogurt which leads to higher consumer acceptability. Addition of 3% aloe vera to 1% fat (AGY3) containing buffalo milk yogurt was found to best for physicochemical as well as organoleptic characteristics as well as organoleptic characteristics.

Promising alternative gum: Extraction, characterization, and oxidation of the galactomannan of Cassia fistula

Galactomannan extracted from Cassia fistula seed endosperm present little data related to the its structural characterization. This study reports the chemical characterization of the galactomannan from Cassia fistula (CF) and their oxidized derivatives. The extracted CF presented a yield of 26.5% (w/w) and the intrinsic viscosity [η] was 9.73 dL/g. 1D and 2D nuclear magnetic resonance spectroscopy (NMR) confirmed that the polysaccharide has a backbone of 4-linked β-D-mannose units, and contains galactose units as pending groups. These galactose units are linked to the central core through a (1→6) linkage and the galactomannan presented Man/Gal ratio of 3.1/1. The galactomannan from Cassia fistula presents low cytotoxicity in Vero cells with a CC₅₀ > 1000 μg/ml. The properties of CF resemble other commercially important galactomannans such as Locust bean gum. Three oxidized derivatives of CF were produced by periodate oxidation, which were carefully characterized by different structural techniques. It was observed that as the degree of oxidation increased, there was an increase in the Man/Gal ratio and a reduction in molar mass and viscosity. The polialdehyde produced may be explored as a versality material to react with amine group of the protein and amined polysaccharide to produce biomaterials.

Physiochemical, rheological, microstructural, and antioxidant properties of yogurt using monk fruit extract as a sweetener

A yogurt using monk fruit extract (MFE) as a sweetener was developed. The aim of the study was to investigate the viability of using MFE to develop sweetened yogurts without the calories of added sugar. The physiochemical, rheological, microstructural, and antioxidant properties of yogurt were studied. Rheological results showed that MFE affected the yogurt fermentation process and its rheological properties. Yogurt sweetened with MFE had similar microstructural properties to yogurt sweetened with sucrose. Yogurt with MFE showed higher levels of gly-pro-p-nitroanilide and dipeptidyl peptidase IV inhibitory activities, 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity, α-glucosidase inhibitory activities, and superoxide anion radical scavenging ability compared with other yogurt samples. Results indicated that MFE could be a novel sweetener and a food antioxidant for functional yogurt and related products.