Analysis of Fat and Protein Content in Milk Using Laser Polarimetric Scatterometry

Monitoring the composition of milk products is an important factor in the management of dairy farms and industry. Information on the quantitative content of milk components is necessary to control milk quality, as well as to optimize dairy cow nutrition and diagnose their clinical condition. The content of fat and protein is considered the main criterion for determining the market value of milk. Increasing the efficiency of dairy production requires the use of inexpensive and compact devices that are capable of performing multicomponent analysis of milk both directly on the farm and in technological lines. We investigated the possibility of fast simultaneous determination of fat and protein content in milk by laser polarimetric scatterometry. The block-diagonal elements of the scattering matrix were measured for a series of commercially produced milk samples with the indicated fat percentage, which were diluted by volume with water. From the measured scattering matrices, the size distributions of fat droplets and casein aggregates were reconstructed. Using the size histograms, the content of fat and protein and protein-to-fat ratio in the studied milk samples are estimated.

Effect of Vitamin C Source on Its Stability during Storage and the Properties of Milk Fermented by Lactobacillus rhamnosus

The enrichment of commonly consumed foods with bioactive components might be helpful in promoting health and reducing the risk of disease, so the enrichment of probiotic fermented milk with vitamin C can be considered appropriate. The effect of vitamin C addition depends on the source of origin (rosehip, acerola and ascorbic acid in powder form) on the growth and survival of Lactobacillus rhamnosus and the quality of fermented milk on the 1st and 21st day of storage was analyzed. The pH, total acidity, vitamin C, syneresis, color, texture profile and numbers of bacterial cells in fermented milk were determined. The organoleptic evaluation was also performed. The degradation of vitamin C in milk was shown to depend on its source. The lowest reduction of vitamin C was determined in milk with rosehip. The least stable was vitamin C naturally found in control milk. The addition of rosehip and acerola decreased syneresis and lightness of milk color, increasing the yellow and red color proportion. In contrast, milk with ascorbic acid was the lightest during the whole experimental period and was characterized by a very soft gel. The growth of Lactobacillus rhamnosus during fermentation was most positively affected by the addition of rosehip. However, the best survival of Lactobacillus rhamnosus was demonstrated in milk with acerola. On the 21st day of storage, the number of L. rhamnosus cells in the control milk and the milk with vitamin C was >8 log cfu g−1, so these milks met the criterion of therapeutic minimum. According to the assessors, the taste and odor contributed by the addition of rosehip was the most intense of all the vitamin C sources used in the study.

PSXIII-28 Late-Breaking: Lactational performance of dairy cows receiving supplemental His: A meta-analysis

The objective of this meta-analysis was to examine the effect of supplemental histidine (His) on dry matter intake (DMI), milk (MY) and energy-corrected milk (ECM) yields, and milk components in lactating dairy cows. A comprehensive meta-analysis was performed to data from 20 studies published in peer-reviewed journals between 1999 and 2021. In 12 of the studies His was supplemented to the diet as rumen-protected His and in the remaining experiments free His was infused into the abomasum (5 experiments), the jugular vein (2 experiments) or the duodenum (1 experiment) of the cows. The diets were based on corn silage in 60% and on grass silage in 40% of the studies. In studies where data were available (13 out of 20), metabolizable protein supply was estimated to be on average 98% (min = 85% and max = 110%) of NRC (2001) requirements. Computations were carried out using Comprehensive Meta-Analysis (V. 3.3.070). Histidine supplementation increased (P < 0.001) plasma His concentration by 59%, compared with control. Dry matter intake and MY increased (P ≤ 0.002) by 0.22 and 0.36 kg/d, respectively, whereas ECM yield tended to increase (P = 0.07) by 0.14 kg/d with His supplemented diets vs. the control. Milk protein concentration was also increased (P = 0.004) by 0.20 %-units, whereas milk fat concentration tended to decrease (P = 0.10) by 0.11 %-units with His supplementation. Further, His increased milk protein and lactose yield (P ≤ 0.05) by 0.31 and 0.14 kg/d, respectively. Overall, based on the available data, His supplementation of lactating dairy cow rations enhanced DMI, MY and milk protein concentration and yield.

Does algae β-glucan affect the fecal bacteriome in dairy calves?

β-glucans has been reported to be associated with many health-promoting and improvements in animal performance, however, information about their effects on the bacterial community remains unknown. This study aimed to investigate how the addition of β-glucans can affect the fecal bacterial community with possible consequences on animal growth and health. For this, newborn Holstein calves (n = 14) were individually housed in tropical shelters and blocked according to sex, date, and weight at birth and randomly assigned to one of the following treatments: (1) Control: milk replacer (14% solids, 24% CP, 18.5% fat); (2) β-glucans: milk replacer supplemented with β-glucans (2 g/d). All calves were bucket fed 6 L/d of milk replacer and received water and starter concentrate ad libitum starting on d 2. To evaluate the bacteriome, fecal samples were collected at weeks 1, 2, 4, and 8. The bacterial community was assessed through sequencing of the V3-V4 region of the 16S rRNA gene on the Illumina MiSeq platform and analyzed using the DADA2 pipeline. No differences for Shannon and Chao1 indexes were observed for treatments, but both indexes increased with age (P < 0.001). There were dissimilarities in the structure of the bacterial community during the pre-weaning period (P = 0.01). In a deeper taxonomic level, Collinsella (Actinobacteriota), Prevotella (Bacteroidota), and Lactobacillus (Firmicutes) were the most abundant genera (9.84, 9.54, and 8.82% of the sequences, respectively). β-glucans promoted a higher abundance of Alloprevotella and Holdemanella, which may indicate a beneficial effect of supplementation on dairy calves. The bacterial community was highly correlated with the fecal score at weeks 1 and 2 and with starter concentrate intake at week 8. In conclusion, algae β-glucan supplementation could be beneficial to fecal bacteriome and consequently to the health and performance of dairy calves.

Production of whey protein hydrolyzates and its incorporation into milk

Whey proteins provide an excellent source of low-molecular-weight bioactive peptides with important functional properties and bioactivities like antihypertensive, opioid, and antimicrobial effects. Presence of peptide molecules with lower molecular weight has a great role in food for health promotion. In this investigation, the release of low-molecular-weight peptides from whey protein concentrate was attempted by using enzymatic digestion. The hydrolyzate was then incorporated into milk to obtain enriched milk (EM) with low-molecular-weight peptides. Based on sensory analysis of EM, electrophoretic and RP-HPLC studies, hydrolyzates of 10% protein (degree of hydrolysis 5%; enzyme/ substrate E/S, 1:50) were finally incorporated into milk at 20% (v/v) to develop an acceptable product enriched with low-molecular-weight peptides. EM had higher protein content, viscosity and emulsifying properties than control milk with 3% fat. It is recommended that EM should not be sterilized as it results in coagulation, but can be safely pasteurized and spray dried without any undesirable effects. Maximum ACE-inhibition activity was obtained in hydrolyzate, followed by EM. This study is expected to boost the opportunity for the dairy industry to venture further into the nutraceutical dairy market. Graphical abstract

Polymorphism of CSN1S1 (g.12164G>A) and CSN2 (g.8913C>A) genes in pure and cross dairy goats

Casein genes directly control milk protein of animals. CSN1S1 (αS1-Casein) and CSN2 (β-Casein) genes influence on milk protein fractions. Genetic polymorphisms of CSN1S1 gene at g.12164G>A locus and CSN2 gene at g.8913C>A locus were identified by PCR-RFLP technique. Animal samples were pure dairy goats providing PE (5 hds.), Saanen (8 hds.) and their crosses providing Sapera (50% Saanen, 50% PE) (51 hds.) and SaanPE (75% Saanen, 25% PE) (3 hds.) from IRIAP dairy goat station. Allele frequency, genotype frequency, heterozygosity value, and Hardy-Weinberg (H-W) equilibrium value were analyzed by Popgen32 program. CSN1S1_g.12164G>A locus resulted in two alleles, i.e. G allele (192 bp, 145 bp, and 101 bp) and A allele (337 bp and 101 bp). The G allele from the highest frequenciest was successively Saanen (0.625), Sapera (0.578), PE (0.400), and SaanPE (0.333). Most dairy goats were heterozygote (Ho>He) and in H-W equilibrium (q2 count < q2P0.05). Whereas CSN2_g.8913C>A locus was monomorphic for possesing only C allele (233 bp and 162 bp), without A allele (416 bp). The existent g.12164G>A SNP of the CSN1S1 gene of could be a potencial molecular selection marker of milk protein content in dairy goat.

Anti-staphylococcal effect of cinnamaldehyde in milk

The survival of Staphylococcus aureus in inoculated (105 colony forming units [CFU]/mL) 3.2% and 0.5% fat ultra-high temperature-pasteurized milk samples containing 0%, 0.05%, or 0.1% cinnamaldehyde stored at 4°C or 10°C was evaluated within 15 days. S. aureus populations reached 7.92 (0.5% fat) and 7.95 (3.2% fat) log CFU/mL in control milk samples stored at 10°C, while in milk sample stored at 4°C, S. aureus counts remained almost unchanged. At the end of the study, the number of this pathogen decreased by 1.52–4.04 log CFU/mL in milk treated with cinnamaldehyde. The greatest anti-staphylococcal effect was achieved in low-fat milk at 10°C and treated with 0.1% cinnamaldehyde.

Effect of faba bean and chickpea mucilage incorporation in the structure and functionality of kefir

This investigation aimed to investigate the viability of kefir enrichment with mucilage extracted from faba bean and chickpea. Four formulations of kefir were studied: fermented milk (control), milk with 3% of faba bean mucilage, milk with 3% of chickpea mucilage and milk with 3% of inulin from artichoke (as prebiotic control). Kefirs were evaluated during 28 days’ storage time at refrigerated temperature. Microbial viability, physicochemical properties (total titratable acidity, syneresis and pH), rheological properties (flow and dynamic shear rheology) and consumer’s acceptability were evaluated. The number of bacteria significantly increased during storage period in all the formulations. The pH decreases during storage whereas total titratable acidity increased as was expected. Kefir supplemented with mucilage showed slightly lower but not significantly different sensory acceptability scores in comparison to the control. The novel mucilage ingredients could be prebiotic source for improving kefir quality.

Nutritional Profile and Organoleptic Qualities of Milk Chocolate Incorporated with Different Spices

An innovative spicy chocolate was developed in this study by partial replacement of cocoa nibs with different selected spice powders of: Ginger (G11), Garlic (G12), Clove (C13), Cinnamon, (C14), Turmeric (T15), Aframomum danielli (A16), Aframomum melegueta (A17), Thyme (T18), Black Pepper (B19) and Clappertonia (C20). Milk chocolate without spices (C10) served as Control. The proximate compositions were carried out using standard methods. The Total Calorific values (TCV) was determined using the Atwater factors (physiological fuel values) of 4kcal, 4kcal and 9kcal per gram of carbohydrate, protein and fat respectively. The sensory evaluation was carried out by panel of tasters consisting of 13 males and 18 female staff of the Cocoa Research Institute of Nigeria who were used to consuming chocolates. The result showed significant differences in the proximate chemical compositions of the chocolates (p<0.05). Apart from black pepper with a An significantly lower protein and ash contents when compared to the control chocolate, all the other spices significantly caused an increase in percentage protein and ash in the control milk chocolate. The trend of protein increase is T18 > G11 > T15 > C20 =A17 > A16 > C14 > C13 > G12 > C10 > B19 > respectively. The range of values obtained for the proximate compositions were (%)The Total Calorific Value (TCV) also showed significant differences among all the samples at p<0.05 with the TCV of the control chocolate being the highest. The addition of spices contributed to acceptable tastes, aroma, flavor and general acceptability of milk chocolates. In Conclusion, this study showed that the incorporation of Spices in chocolate increased the protein and ash content of milk chocolate, the organoleptic acceptance while reducing the TCV values This is a desirable findings in view of the fear of high calorific values of Milk Chocolate which may predispose consumers to Obesity when consumed.in large quantities.