Functional, nutritional, and sensorial evaluation of sorghum-based beverages produced by single- and two-stage acid, α-amylase enzyme, and germination treatments.

Nowadays, the consumption of functional foods, such as plant-based beverages, is increasing due to their health-promoting properties. The low extraction yield of nutritional and functional components is considered a major challenge during the production of sorghum-based beverages (SBB), as well as their sensorial properties. This investigation studied the effects of various treatments (acidic using phosphoric acid, enzymatic using α-amylase, germination, germination-acidic, germination-enzymatic, and acidic-enzymatic) on the functional, nutritional, and sensorial properties of SBB. The two-stage acidic-enzymatic treatment demonstrated the highest extraction yield, dry matter, ash, carbohydrates, and reducing sugar contents, as well as the lowest starch content (p < .05). Furthermore, the highest protein content (0.98%) was achieved by the germination treatments of sorghum grains. While the highest fat content was achieved by the acidic treatment (1.38%), the germination-acidic treatment exhibited the highest energy value (26.02 kcal/100 mL). Moreover, the total phenolic content of the acidic-enzymatic treatment (44.56 mg GAE/L) was significantly higher than that of other treatments. However, all treatments demonstrated lower antioxidant properties compared to the control treatment (142.85 mg BHT eq./L). Furthermore, the sensory evaluation of the germination and germination-enzymatic treatments showed acceptable scores (≥7) for consumers. In conclusion, the results indicated that the two-stage treatments of sorghum, especially the acidic-enzymatic treatment, were more effective than single treatments for the extraction of functional and nutritional components during the production of SBB.

Determination of volatile compounds in white brine cheese and ultrafiltered cheese during ripening and shelf-life using nano-adsorbent fibers.

In this study, determination of aromatic compounds in cheese samples was performed by headspace solid-phase microextraction (HS-SPME) using a new adsorbent as a novel coated fiber in combination with a gas chromatography/mass spectrometry or flame ionization detector to evaluate the changes during ripening. Brine and ultrafiltrated (UF) cheese were sampled via HS-SPME and analyzed by gas chromatography/mass spectrometry. Polysulfone and mesoporous carbon nitride were used as two types of fibers for coating. The results showed that the pH had significant decreased during the 120 days for brine cheese (p < 0.001), and during the 90 days (p < 0.001) for UF cheese. Acidity was relatively stable during the ripening period for both cheeses (p > 0.05). Protein content decreased during the ripening period for both cheeses (p < 0.001). Moisture content also significantly decreased during the ripening period for both cheeses (p < 0.001). 74 compounds were identified in brine cheese and 27 major components in UF cheese. Fatty acids were the predominant components, followed by aldehydes (n: 17, 22.9%), alcohol (n; 12, 16.2%), ester (n: 11, 14.8%), alkane (n: 7, 9.4%), and ketone (n: 6, 8.1%) for white brine cheese, while for UF cheese fatty acid (n: 12, 44.4%) and aldehyde (n: 5, 18.5%), alcohol (n: 3, 11.1%), ketone (n: 3, 11.1%), ester (n: 2, 7.4%) and alkane (n: 1, 3.7%).

Computing Accurate Probabilistic Estimates of One-D Entropy from Equiprobable Random Samples.

We develop a simple Quantile Spacing (QS) method for accurate probabilistic estimation of one-dimensional entropy from equiprobable random samples, and compare it with the popular Bin-Counting (BC) and Kernel Density (KD) methods. In contrast to BC, which uses equal-width bins with varying probability mass, the QS method uses estimates of the quantiles that divide the support of the data generating probability density function (pdf) into equal-probability-mass intervals. And, whereas BC and KD each require optimal tuning of a hyper-parameter whose value varies with sample size and shape of the pdf, QS only requires specification of the number of quantiles to be used. Results indicate, for the class of distributions tested, that the optimal number of quantiles is a fixed fraction of the sample size (empirically determined to be ~0.25-0.35), and that this value is relatively insensitive to distributional form or sample size. This provides a clear advantage over BC and KD since hyper-parameter tuning is not required. Further, unlike KD, there is no need to select an appropriate kernel-type, and so QS is applicable to pdfs of arbitrary shape, including those with discontinuous slope and/or magnitude. Bootstrapping is used to approximate the sampling variability distribution of the resulting entropy estimate, and is shown to accurately reflect the true uncertainty. For the four distributional forms studied (Gaussian, Log-Normal, Exponential and Bimodal Gaussian Mixture), expected estimation bias is less than 1% and uncertainty is low even for samples of as few as 100 data points; in contrast, for KD the small sample bias can be as large as -10% and for BC as large as -50%. We speculate that estimating quantile locations, rather than bin-probabilities, results in more efficient use of the information in the data to approximate the underlying shape of an unknown data generating pdf.

Characterization of a traditional ripened cheese, Kurdish Kope: Lipolysis, lactate metabolism, the release profile of volatile compounds, and correlations with sensory characteristics.

Kope cheese has been characterized based on gross chemical composition, free fatty acids (FFAs), organic acids (OAs), volatile compounds (VCs), and sensory attributes (SAs) during 187 days of the ripening period. C16:0, C18:1cisΔ9, and C14:0 were the most abundant FFAs. Lactic and acetic acids were the most prevalent OAs affecting sensory properties. principal component analysis (PCA) indicated that butanoic acid, butyl hexanoate, and 2,3-butanediol were as key VCs. Protein contents, pH (based on FFA and OA), salt in the moisture (S/M), and water activity (aw ) (based on VC and SA) were highly correlated with PC2, resulted in two distinct groups. Based on lipolysis and glycolysis studies, early-ripened cheese samples showed lipolysis and lactate metabolism more intensely compared to medium and old-ripened ones. Based on the data of VC and SA, the samples may be classified into three groups: (1) early-ripened cheeses with a salty taste, waxy to cheesy odor, and rubbery texture, (2) medium-ripened cheese with a sweet taste and cheesy odor, and (3) old-ripened cheese with a bitter taste, cheesy to pungent odor, a firm and fragile texture. Textural attributes were highly correlated with proteolysis indices and pH. The results of sensory desirability indicated a significant correlation with pungency, bitterness, and OAs. The cheese samples ripened on the day 127 were selected as the most desirable product. Ripening time had a significant effect on the chemical composition, especially on S/M, pH, and aw  parameters, which determine the pattern as well as the intensity of biochemical pathways and the final sensory attributes. PRACTICAL APPLICATION: The current study intends to characterize and develop a standardized procedure for producing a traditional cheese called "Kope cheese" by determining the appropriate duration time for the ripening process, determining the main chemical/biochemical compounds that are highly correlated with its unique flavor and texture and distinguishing the key processing factors (such as curd salting, pH values during brining) that have to be altered or controlled carefully during the manufacturing process. The data would help cheese manufacturers determine the optimum time of ripening in order to achieve the best flavor and texture attributes in the final product.

Effect of a dietary supplement composed of hydrolyzed milk proteins and vanillin on the reduction of infection and oxidative stress induced by chemotherapy.

This study evaluates the antioxidant and antibacterial activity of a mixture of lactoferrin hydrolysate (LfH), whey protein hydrolysate (WPH) and vanillin in vitro and in vivo to design a chemoprotective supplement for reducing the infection and oxidative stress induced by chemotherapy. The designed supplement showed significant antibacterial activity against E. coli. The supplement with the highest concentration exhibited considerable antioxidant activity in (2,2-diphenyl-1-picrylhydrazyl) DPPH free radicals, (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) ABTS, and reducing power assays. In the biochemical analysis of liver homogenate, the supplement 3 increased the level of enzymes Catalase (CAT), Glutathione peroxidase (GPx), Superoxide dismutase (SOD), and also the Ferric Reducing Ability of Plasma (FRAP) while decreased thiobarbituric acid reactive substances (TBARS) in comparison to paclitaxel group, indicative of activity against oxidative stress. Antibacterial and antioxidant activity of the designed supplement makes it a good candidate for use as a functional food to reduce the side effects of chemotherapy. PRACTICAL APPLICATIONS: A dietary supplement composed of lactoferrin hydrolysate (LfH), whey protein hydrolysate (WPH) and vanillin showed antibacterial activity against E. coli and S. aureus in vitro. The studied supplement also exhibited significant antioxidant properties in the model system and anti-oxidative stress activity in mice exposed to paclitaxel. This supplement has a potential for use in the food matrix to reduce the chemotherapy side effects and to act as a chemoprotective agent.

Promoting Probiotics Survival by Microencapsualtion with Hylon Starch and Genipin Cross-linked Coatings in Simulated Gastro-intestinal Condition and Heat Treatment.

Microencapsulation with hydrocolloids as a modern technique has been used to prolong the survival of probiotics during exposure to harsh conditions. In this study, alginate-Hylon starch microcapsules with genipin cross-linked chitosan and poly-L-lysine coatings were developed to encapsulate four strains of probiotic bacteria, including Lactobacillus casei (ATCC 39392), Bifidobacterium bifidum (ATCC 29521), Lactobacillus rhamnosus (ATCC 7469), and Bifidobacterium adolescentis (ATCC 15703). The viability of probiotics was investigated under heat treatment (72, 85, and 90 °C, 0.5 min), simulated gastric juice (along with pepsin, pH = 2, 2 h at 37 °C), and simulated intestinal juice (along with pancreatin and bile salts, pH = 8, 2 h at 37 °C). The morphology and size of microcapsules were measured by scanning electron and optical microscopy. Results of this research demonstrated that, compared with the free form, microencapsulated probiotics had significantly (P < 0.05) higher viability under simulated gastro-intestinal conditions and heat treatment. Microcapsules with genipin cross-linking significantly increased the viability of probiotics compared with non-cross-linked microcapsules. Moreover, genipin did not influence the size of the microcapsules produced using the emulsion technique. In general, this research indicated that the presence of genipin as a cross-linking agent in the structure of hydrocolloids such as chitosan and poly-L-lysine, and also the presence of Hylon (high-amylose starch) as a material resistant to heat and digestive enzymes, not only increased the viability of probiotics in simulated human gastro-intestinal condition but also considerably improved the thermal resistance of microcapsules.

Antioxidant Capability of Ultra-high Temperature Milk and Ultra-high Temperature Soy Milk and their Fermented Products Determined by Four Distinct Spectrophotometric Methods.

BACKGROUND: Due to the recent emerging information on the antioxidant properties of soy products, substitution of soy milk for milk in the diet has been proposed by some nutritionists. We aimed to compare four distinct antioxidant measuring methods in the evaluation of antioxidant properties of industrial ultra-high temperature (UHT) milk, UHT soy milk, and their fermented products by Lactobacillus plantarum A7. MATERIALS AND METHODS: Ascorbate auto-oxidation inhibition assay, 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical scavenging method, hydrogen peroxide neutralization assay and reducing activity test were compared for the homogeneity and accuracy of the results. RESULTS: The results obtained by the four tested methods did not completely match with each other. The results of the DPPH assay and the reducing activity were more coordinated than the other methods. By the use of these methods, the antioxidant capability of UHT soy milk was measured more than UHT milk (33.51 ± 6.00% and 945 ± 56 µM cysteine compared to 8.70 ± 3.20% and 795 ± 82 µM cysteine). The negative effect of fermentation on the antioxidant potential of UHT soy milk was revealed as ascorbate auto-oxidation inhibition assay, DPPH method and reducing activity tests ended to approximately 52%, 58%, and 80% reduction in antioxidant potential of UHT soy milk, respectively. CONCLUSIONS: The antioxidative properties of UHT soy milk could not be solely due to its phenolic components. Peptides and amino acids derived from thermal processing in soy milk probably have a main role in its antioxidant activity, which should be studied in the future.

The encapsulation of flavourzyme in nanoliposome by heating method.

The main objective of this study was to use heating method (HM) to prepare liposome without employing any chemical solvent or detergent. Plackett-Burman design (PBD) was applied for the screening of significant process variables including the lecithin proportion, the cholesterol/lecithin ratio, the pH of solution for liposome preparation, the enzyme/lecithin ratio, the stirring time, the process temperature, the speed of stirrer, the ratio of stirrer to the tank diameter, the application of homogenization, the method of adding enzyme and centrifugation conditions on the encapsulation efficiency (EE %) of liposome and the activity of liposomal Flavourzyme (LAPU(-1)) (P < 0.05). Then, the response surface methodology based on the central composite design (CCD) was applied for the evaluation of the impacts of the significant mentioned variables on the EE (%) and the activity of the liposomal Flavourzyme. The results indicated that the lecithin proportion and the stirring time were the major influential variables for both responses. The most suitable formulation of the Flavourzyme-loaded liposome is 4.5 % lecithin, 45 °C temperature, 5 % Flavourzyme/lecithin ratio, 30 min stirring time and medium pH of 6. Under suitable operating conditions, the EE of liposome and the activity of the liposomal Flavourzyme were achieved as 26.5 % and 9.96 LAPU ml(-1), respectively. AFM technique and size distribution clearly showed the diameter of 189 nm for the spherical shape of the Flavourzyme- loaded nanoliposome.

Effect of refrigerated storage on the probiotic survival and sensory properties of milk/carrot juice mix drink

Background: There is a genuine interest in the development of probiotic milk and juice based beverages because they are a good-vehicle to deliver probiotic microorganisms to consumers. For this purpose, the viability and metabolism of four probiotic strains (Lactobacillus acidophilus LA5, Bifidobacterium lactis BB12, L. rhamnosus and L. plantarum) were studied in non-fermented milk and carrot juice mix drink. The drinks were evaluated in 5 days interval for viable cell count, pH, acidity, sedimentation and sensory quality during refrigerated storage at 4 ± 2ºC for up to 20 days. Results: The results showed that all strains had good viability in milk/carrot juice drink (88-98%), but L. acidophilus LA5 seemed more stable than three other strains. The levels of pH and acidity were ranged 5.33-6.6 and 0.13-0.31%, respectively. The drinks inoculated with L. rhamnosus and control (non-probiotic) showed more variation in pH and acidity. The most sedimentation was detected in drinks inoculated with L. rhamnosus, reaching 3.73 mL/10 mL sample. Sensory assessment indicated lowest acceptability in control and milk/carrot juice drink inoculated with L. rhamnosus, respectively. Conclusion: This study indicated that some probiotic bacteria can be applied by food producers to produce functional drinks with an increased shelf-life.

An evaluation and partial characterization of a bacteriocin produced by Lactococcus lactis subsp lactis ST1 isolated from goat milk

A bacteriocin-like inhibitory substance producing Lactococcus lactis subsp lactis strain, ST1, isolated from goat milk of Iranian origin and with broad spectrum of activity and desirable technical properties was used for evaluating some futures of bacteriocin inhibitory activity. Cell growth and bacteriocin production studies were carried out in MRS medium incubated statically under uncontrolled pH condition. The antibacterial activity presented a primary metabolite pattern and showed a rapid decrease at the stationary phase. Microaerobiosis and capnophily growth conditions resulted in higher bacteriocin production while aerobiosis showed negative effect on both cell growth and bacteriocin production. Bacteriocin production, on the other hand, was favored in MRS broth (pH; 6.5) inoculated with 0.1 ml l-1 fresh culture when incubation was carried out at 30 °C. This indicated that the conditions resulted in higher levels of growth were frequently favoring bacteriocin production by ST1 as well. Decrease in activity, at the stationary growth phase, was much pronounced in favored growth condition. Nutrient depletion, deferent effect of low pH on bacteriocin production and/or protein degradation seemed more responsible for this phenomenon. The study also provided further data on new method for bacteriocin release from the cell wall of producer. It was clearly shown that both heating and ultrasound shock for 5 min at pH 2 could increase bacteriocin activity significantly. The release was more pronounced in the presence of 0.5% Tween80.

An evaluation and partial characterization of a bacteriocin produced by Lactococcus lactis subsp lactis ST1 isolated from goat milk.

A bacteriocin-like inhibitory substance producing Lactococcus lactis subsp lactis strain, ST1, isolated from goat milk of Iranian origin and with broad spectrum of activity and desirable technical properties was used for evaluating some futures of bacteriocin inhibitory activity. Cell growth and bacteriocin production studies were carried out in MRS medium incubated statically under uncontrolled pH condition. The antibacterial activity presented a primary metabolite pattern and showed a rapid decrease at the stationary phase. Microaerobiosis and capnophily growth conditions resulted in higher bacteriocin production while aerobiosis showed negative effect on both cell growth and bacteriocin production. Bacteriocin production, on the other hand, was favored in MRS broth (pH; 6.5) inoculated with 0.1 ml l(-1) fresh culture when incubation was carried out at 30 °C. This indicated that the conditions resulted in higher levels of growth were frequently favoring bacteriocin production by ST1 as well. Decrease in activity, at the stationary growth phase, was much pronounced in favored growth condition. Nutrient depletion, deferent effect of low pH on bacteriocin production and/or protein degradation seemed more responsible for this phenomenon. The study also provided further data on new method for bacteriocin release from the cell wall of producer. It was clearly shown that both heating and ultrasound shock for 5 min at pH 2 could increase bacteriocin activity significantly. The release was more pronounced in the presence of 0.5% Tween80.

Biological activity of camel milk casein following enzymatic digestion.

The aim of this study was to investigate the effects of enzymatic hydrolysis with digestive enzymes of camel whole casein and beta-casein (ß-CN) on their antioxidant and Angiotensin Converting Enzyme (ACE)-inhibitory properties. Peptides in each hydrolysate were fractionated with ultra-filtration membranes. The antioxidant activity was determined using a Trolox equivalent antioxidant capacity (TEAC) scale. After enzymatic hydrolysis, both antioxidant and ACE-inhibitory activities of camel whole casein and camel ß-CN were enhanced. Camel whole casein and ß-CN showed significant ACE-inhibitory activities after hydrolysis with pepsin alone and after pepsinolysis followed by trypsinolysis and chymotrypsinolysis. Camel ß-CN showed high antioxidant activity after hydrolysis with chymotrypsin. The results of this study suggest that when camel milk is consumed and digested, the produced peptides start to act as natural antioxidants and ACE-inhibitors.

Improvement of the antimicrobial and antioxidant activities of camel and bovine whey proteins by limited proteolysis.

The compositions and structures of bovine and camel milk proteins are different, which define their functional and biological properties. The aim of this study was to investigate the effects of enzymatic hydrolysis of camel and bovine whey proteins (WPs) on their antioxidant and antimicrobial properties. After enzymatic treatment, both the antioxidant and the antimicrobial activities of bovine and camel WPs were improved. The significantly higher antioxidant activity of camel WPs and their hydrolysates as compared with that of bovine WPs and their hydrolysates may result from the differences in amounts and/or in accessibilities of antioxidant amino acid residues present in their primary structures and from the prevalence of alpha-lactalbumin and beta-lactoglobulin as proteolytic substrates in camel and bovine whey, respectively. The results of this study reveal differences in antimicrobial and antioxidant activities between WP hydrolysates of bovine and camel milk and the effects of limited proteolysis on these activities.

Chaperone activities of bovine and camel beta-caseins: Importance of their surface hydrophobicity in protection against alcohol dehydrogenase aggregation.

Beta-casein (beta-CN) showing properties of intrinsically unstructured proteins (IUP) displays many similarities with molecular chaperones and shows anti-aggregation activity in vitro. Chaperone activities of bovine and camel beta-CN were studied using alcohol dehydrogenase (ADH) as a substrate. To obtain an adequate relevant information about the chaperone capacities of studied caseins, three different physical parameters including chaperone constant (k(c), microM(-1)), thermal aggregation constant (k(T), degrees C(-1)) and aggregation rate constant (k(t), min(-1)) were measured. Bovine beta-CN displays greater chaperone activity than camel beta-CN. Fluorescence studies of 8-anilino-1-naphthalenesulfonic acid (ANS) binding demonstrated that bovine beta-CN is doted with larger effective hydrophobic surfaces at all studied temperatures than camel beta-CN. Greater relative hydrophobicity of bovine beta-CN than camel beta-CN may be a factor responsible for stronger interactions of bovine beta-CN with the aggregation-prone pre denatured molecular species of the substrate ADH, which resulted in greater chaperone activity of bovine beta-CN.