A Metabolomics Approach to Establish the Relationship between the Techno-Functional Properties and Metabolome of Indian Goat Yoghurt.

INTRODUCTION: Goat milk has poorer fermentation characteristics due to the absence or only traces of αs1-casein, due to which goat yoghurt contains a less dense gel structure. Moreover, the fermentation characteristics of the milk vary between the breeds of the same species. Therefore, it becomes imperative to explore a few metabolites which could regulate the techno-functional properties of goat yoghurt. OBJECTIVES: This study was aimed at relating the metabolite profile of yoghurt prepared from milk of Barbari, an indigenous goat breed of India, and its techno-functional properties (firmness, whey syneresis, and flow behaviour) using multivariate data analysis and regression models. RESULTS: Goat yoghurt was prepared with two different total solids (TS) levels (12 and 16%) and cultures, namely, commercial culture comprising a thermophilic yoghurt culture (A) and NCDC-263 comprising a mixed yoghurt culture (B). Results demonstrated a significant difference (p < 0.05) in whey syneresis with the increase in the TS level. Flow behaviour of all yoghurt samples showed a decrease in viscosity with an increase in shear rate, which confirmed its non-Newtonian behaviour and shear thinning nature, whereas frequency sweep confirmed its viscoelastic nature. Firmness was the most affected under the influence of different TS and culture levels. It was higher (p < 0.05) for 16-A, followed by 16-3B, and minimum for 12-2B. GC-MS-based metabolomics of the yoghurt revealed a total of 102 metabolites, out of which 15 metabolites were differentially expressed (p < 0.05), including 2-hydroxyethyl palmitate, alpha-mannobiose, and myo-inositol. Multivariate data analysis revealed clear separation among groups using principal component analysis and several correlations using a correlation heat map. Further, regression analysis exhibited methylamine (0.669) and myo-inositol (0.947) with higher regression coefficients (R2 values) exceeding 0.6, thus demonstrating their significant influence on the techno-functional properties, mainly firmness, of the yogurt. CONCLUSION: In conclusion, A gas chromatography-based metabolomics approach could successfully establish a relationship between the metabolome and the techno-functional properties of the yoghurt.

Biosynthesis of lactobionic acid: a systematic review.

Lactobionic acid is a comparatively less explored lactose derivative with impressive biofunctional qualities, and is currently being used by the advanced chemical and pharmaceutical research industries. It is an aldonic acid with probiotics, antimicrobial, antioxidant, calcium chelating activity. In dairy and food products, it can be used to improve flavor, texture, yield and shelf life with additional health benefits. The biochemical method for producing lactobionic acid makes it safe for humans to consume as food or medicine. This systematic review describes the various bioproduction methods of lactobionic acid. This study emphasizes the production method, conversion rate, and specific yield of various microorganisms and enzymes employed in biosynthesis of lactobionic acid. Scopus advanced search is used for database mining. Original, traceable peer-reviewed research articles directly related to lactobionic acid are selected for this systematic review. The selected articles are grouped for ease of discussion and understanding. In the last 75 years, several bioproduction methods of lactobionic acid have been developed. By fine-tuning the microbial incubation conditions, the productivity of lactobionic acid can be significantly improved. The oxidoreductase enzymes responsible for the conversion of lactose can be purified from the system by advanced membrane technology. In the presence of a suitable redox mediator and regenerative enzyme, an efficient continuous lactobionic acid production system can be developed. To date, several methods are available for the complete conversion of lactose to lactobionic acid with an impressive specific production rate. This review will help researchers and industries to have better insights and understanding of the bioproduction of lactobionic acid.

Valorization of Sour Buttermilk (A Potential Waste Stream): Conversion to Powder Employing Reverse Osmosis and Spray Drying.

Reverse osmosis (RO) is known for the economic dewatering of dairy streams without any change in phase. At the household level, surplus milk is fermented and churned to obtain butter, which is subsequently heated to obtain clarified milk fat (ghee). The production of 1 kg ghee generates 15-20 kg sour buttermilk (SBM) as a by-product that is mostly drained. This causes a loss of milk solids and environmental pollution. The processing, preservation and valorization of SBM are quite challenging because of its low total solids (TS) and pH, poor heat stability and limited shelf life. This investigation aimed to transform SBM into a novel dried dairy ingredient. SBM was thermized, filtered, defatted and concentrated at 35 ± 1 °C, employing RO up to 3.62× (12.86%). The RO concentrate was subsequently converted into sour buttermilk powder (SBMP) by employing spray drying. SBMP was further characterized for its physicochemical, reconstitution and functional properties; rheological and morphological characteristics; and amino acid and fatty acid profiling, along with FTIR and XRD spectra. SBMP was "instant soluble-3 s" and exhibited excellent emulsion stability (80.70%), water binding capacity (4.34 g/g of protein), flowability (28.36°) and antioxidant properties. In nutshell, a process was developed for the valorization of sour buttermilk to a novel dairy ingredient by employing reverse osmosis and a spray-drying process.

An assessment of the intact casein content in natural cheddar cheese to determine its suitability in processed cheeses with desired properties.

As compared to age, intact casein in the natural cheddar cheese is a better index of selection for manufacturing processed cheese. In view of this, the present investigation was designed to establish relation between intact casein of the natural cheese with desirable properties of the processed cheese so that the most desirable intact casein in the natural cheddar cheese can be selected on the basis of required properties of the processed cheese. Processed cheese was prepared by using natural cheddar cheese of different intact casein content (ICC) and analysed for meltability, oiling off and hardness. Multiple linear regression was used for prediction of ICC using meltability, oiling off and hardness and it was observed that the all the independent variables significantly affected ICC. Adjusted R2 value of 0.952 and root mean square error of 1.04 suggested a good fit and validation of the developed equation.

Homogenization and sodium hydrogen phosphate induced effect on physical and rheological properties of ultrafilterd concentrated milk.

Ultrafiltration (UF) of buffalo skim milk (BSM) induces changes in its delicate protein-mineral equilibrium. Appling UF causes alteration in chemical composition of UF retentates as a function of protein concentration that adversely affect their physical and rheological properties. Hence, present investigation was targeted to evaluate the changes taking place in heat stability, ζ-potential, particle size, apparent viscosity, pH, turbidity and crossover temperature of storage (G') and loss (G″) modulus of high-protein BSM based UF retentates as a function of homogenization and sodium hydrogen phosphate (SHP) addition. The UF of BSM (heat treated at 85 ± 1 °C for 5 min), significantly increased (P < 0.05) the concentration of protein, fat and minerals, however, it decreased the concentration of lactose and water soluble minerals in UF retentates over BSM. The SHP addition significantly increased (P < 0.05) pH, crossover temperature of G' and G″, ζ-potential, while significantly decreased (P < 0.05) turbidity and particle size in most non-homogenized retentates. Heat coagulation time (HCT) of control and treated UF retentates were at par (P > 0.05) with each other, however, variations were observed in their viscosity values. Rheological behaviour of most of these UF retentates was efficiently described by Bingham model. The correlation among ζ-potential, particle size, apparent viscosity, pH, turbidity, HCT and crossover temperatures G' and G″ of evaluated samples was also established. Overall, this study concluded that 0.5-6% SHP addition in non-homogenized UF retentates, markedly improved their milk protein stability as advocated by higher ζ-potential, G' and G″ crossover temperature values. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-021-05097-2.

Effect of disodium phosphate and homogenization on physico-chemical and rheological properties of buffalo skim milk based ultrafiltered retentate.

The concentration of pasteurized buffalo skim milk (PBSM) employing ultrafiltration (UF) alters the chemical composition of ultrafiltered retentate that adversely affect its proteins and salts equilibrium. Effect of stabilizing salts addition in concentrated milks or retentates was majorly dedicated to their thermal stability only. Therefore, this study was aimed to investigate the effect of disodium phosphate (DSP) addition and homogenization of 2.40 × UF retentate (0.60 protein to total solids ratio) on its ζ-potential, particle size, heat stability, turbidity, pH, viscosity and crossover temperature of storage (G') and loss (G″) modulus. Concentration of PBSM in UF process, significantly (P < 0.05) increased its percent TS, protein, fat and ash contents, but markedly decreased its lactose content. DSP addition significantly increased (P < 0.05) the ζ-potential, pH, viscosity and particle size in majority of the homogenized and non-homogenized retentates. Homogenized retentates containing 2.5 and 5% DSP exhibited Newtonian and Power law flow behaviour. However, rheological behaviour of non-homogenized retentates containing zero (control), 1 and 4% DSP was best explained by Bingham model. Further, non-homogenized retentates with 0.5, 2, 3, 5% DSP exhibited Newtonian flow, but retentates containing 6 and 7% DSP was best explained by Power law. The correlation among different attributes of DSP added non-homogenized and homogenized samples were also studied. Particle size and turbidity (r = + 0.999, P < 0.05) as well as ζ-potential and crossover temperature of G' and G″ (r = + 0.999, P < 0.05) showed positive correlation in 4% DSP added non-homogenized retentate.

Effect of change in pH, heat treatment and diafiltration on properties of medium protein buffalo milk protein concentrate.

The demand of milk protein concentrate (MPC) powders is continuously increasing as high protein dairy ingredients. Presence of higher calcium and casein contents; heating, ultrafiltration (UF), diafiltration (DF) and spray drying of buffalo skim milk induces undesirable changes in milk proteins that causes problem of poor solubility in MPC powders. Therefore, this investigation was aimed to study the effect of change in pH (6.8-native, 7.0-neutral), heat treatments (74 ± 1 °C/15 s, 80 ± 1 °C/5 min, 85 ± 1 °C/5 min, 90 ± 1 °C/5 min) and DF on physicochemical, functional, reconstitution and rheological properties of medium protein buffalo milk protein concentrate (MP-BMPC) powder. Based on maximum ζ-potential and heat stability, UF retentate was selected, diafiltered and spray dried to obtain MP-BMPC powder. Despite having higher protein content, MP-BMPC powder exhibited markedly better functional (solubility, wettability, viscosity and emulsion stability) properties than buffalo milk protein concentrate 60. The interstitial air content, occluded air content, loose bulk density, packed bulk density, particle density and porosity values of MP-BMPC powder were 145.97 and 112.92 mL 100 g-1 of powder, 0.21 g mL-1, 0.30 g mL-1, 0.55 g mL-1 and 65.09%. Further, its specific surface area; particle size distribution (d10, d50, d90); Sauter (D32) and DeBroukere (D43) mean values were 97.93 m2 kg-1; 34.32, 104.42, 218.58 µm; 61.27 µm and 117.99 µm. The storage modulus (G') and loss modulus (G″) crossover temperature of UF and DF retentates were ~ 57.16 °C and 55.10 °C, respectively. Rheological behaviour of UF, DF retentates and MP-BMPC solution were best explained by Herschel-Bulkley model. Fourier-transform infrared spectroscopy best described amide I, II and III regions in 1700-1400 cm-1 and 1350-1200 cm-1 wavenumber range.

Quantitative descriptive analysis and principal component analysis for sensory characterization of Indian milk product cham-cham.

Promising development and expansion in the market of cham-cham, a traditional Indian dairy product is expected in the coming future with the organized production of this milk product by some large dairies. The objective of this study was to document the extent of variation in sensory properties of market samples of cham-cham collected from four different locations known for their excellence in cham-cham production and to find out the attributes that govern much of variation in sensory scores of this product using quantitative descriptive analysis (QDA) and principal component analysis (PCA). QDA revealed significant (p < 0.05) difference in sensory attributes of cham-cham among the market samples. PCA identified four significant principal components that accounted for 72.4 % of the variation in the sensory data. Factor scores of each of the four principal components which primarily correspond to sweetness/shape/dryness of interior, surface appearance/surface dryness, rancid and firmness attributes specify the location of each market sample along each of the axes in 3-D graphs. These findings demonstrate the utility of quantitative descriptive analysis for identifying and measuring attributes of cham-cham that contribute most to its sensory acceptability.

Properties of sweetened Indian yogurt (mishti dohi) as affected by added tryptic whey protein hydrolysate.

Utilization of Indian sweetened yogurt (colloquially termed as Mishti Dohi), as vehicle for ACE inhibition and antioxidant activity, by added tryptic whey protein hydrolysate (TWPH) (@ 1, 2, 3 % v/milk), was attempted. Yogurt with 3 % TWPH exhibited non-significant (p > 0.05) difference for sensory attributes; but for body & texture; and maximum biofunctional properties, electing it for storage study (5 ± 1 °C). Flavor and body & texture scores registered significant (p < 0.05) decline under 14 days storage. ACE inhibition and antioxidant activity of control increased by 47.95 and 13.18 % and of experimental 24.58 and 13.43 %, correspondingly. Acidity rose to 1.18 % LA. Control samples conveyed 18.07 % and experimental of 20.77 % escalation for wheying-off. Tyrosine value was 27.04 µg.mL(-1). Among rheological attributes, firmness, quantified by texture analyzer TA-XT2i, dropped (p < 0.05), due to decrease of gel rigidity whereas work of adhesion revealed non-significant difference (p > 0.05), throughout.

Discordance between in silico & in vitro analyses of ACE inhibitory & antioxidative peptides from mixed milk tryptic whey protein hydrolysate.

ACE inhibitory and antioxidative peptides identified by LCMS/MS, from mixed milk (Bubalus bubalis and Bos taurus) tryptic whey protein hydrolysate, were compared with the in silico predictions. α la and ß lg sequences, both from Bubalus bubalis and Bos taurus, were used for in silico study. SWISS-PROT and BIOPEP protein libraries were accessed for prediction of peptide generation. Study observed gaps in the prediction versus actual results, which remain unaddressed in the literature. Many peptides obtained in vitro, were not reflected in in silico predictions. Differences in identified peptides in separate libraries were observed too. In in silico prediction, peptides with known biological activities were also not reflected. Predictions, towards generation of bioactive peptides, based upon in silico release of proteins and amino acid sequences from different sources and thereupon validation in relation to actual results has often been reported in research literature. Given that computer aided simulation for prediction purposes is an effective research direction, regular updating of protein libraries and an effectual integration, for more precise results, is critical. The gaps addressed between these two techniques of research, have not found any address in literature. Inclusion of more flexibility with the variables, within the tools being used for prediction, and a hierarchy based database with search options for various peptides, will further enhance the scope and strength of research.

Effect of Acacia Gum, NaCl, and Sucrose on Physical Properties of Lotus Stem Starch.

Consumer preferences in east Asian part of the world pave the way for consumption of lotus stem starch (LSS) in preparations such as breakfast meals, fast foods, and traditional confectioneries. The present study envisaged the investigation and optimization of additives, that is, acacia gum, sodium chloride (NaCl), and sucrose, on water absorption (WA), water absorption index (WAI), and water solubility index (WSI) of LSS employing response surface methodology (RSM). Acacia gum resulted in increased water uptake and swelling of starch; however, NaCl reduced the swelling power of starch by making water unavailable to starch and also due to starch-ion electrostatic interaction. Sucrose restricted the water absorption by binding free water and decreased amylose leaching by building bridges with starch chains and thus forming rigid structure.