Background and objective: Silybum marianum seed extract (silymarin) is rich in phenolic compounds with anti-oxidative activity that add beneficial and healthful properties to silymarin-enriched products. The present study investigated effects of silymarin on characteristics of a functional yogurt.

Material and methods: In this study, yogurt was enriched with Silybum marianum seed extract at concentrations of 0, 25, 50 and 100 mg l^-1 milk and the samples were analyzed for physicochemical and sensory properties and viability of starter bacteria during 21 days at 4°C at 7-day intervals.

Results and conclusion: Results showed that increasing silymarin proportion in yogurt samples increased anti-oxidative activity, total phenolic content, total viability of Lactobacillus delbrueckii and decreased pH value, viscosity and sensory attributes (p<0.05). Furthermore, pH, viscosity, anti-oxidative activity, phenolic compounds and sensory attributes decreased during storage (P<0.05). In conclusion, 25 mg Silybum marianum seed extract per one liter of milk can be used for the preparation of yogurts with healthy properties.

Conflict of interest: The authors declare no conflict of interest.

Background and objective: Monascus purpureus is a filamentous fungus with ability to produce pigments with therapeutic properties. Red pigments are especially used as additives, antioxidants, preservatives and substitutions for nitrites in food technology. To decrease fermentation costs, agro-industrial wastes such as soybean meals have been used as substrates. In the current study, red pigment production by Monascus purpureus on soybean meals was optimized.

Material and methods: In this study, red Monascus pigment production by Monascus purpureus ATCC 16362 was carried out under submerged fermentation using soybean meals as nitrogen sources to replace yeast extracts. Central composite design was used to assess the optimum level of soybean meal replacement (0-100%), ZnSO₄.7H₂O concentration (0-0.02
g l^-1) and thermal stress time of spore suspension at 70°C (50-90 s). Red Monascus pigment and biomass productions were assessed as dependent responses.

Results and conclusion: The maximum production of red Monascus pigment (4.54 AU ml^-1) was achieved under conditions of soybean meal replacement of 79.72%, ZnSO₄.7H₂O concentration of 0-0.02 g l^-1 and thermal stress time of spore suspension of 81.89 s. The average yield of red Monascus pigment, conversion factor of biomass in red pigment Y_P/X and cell productivity included 0.324 AU ml^-1 day^-1, 1.10 AU L g^-1 and 0.292 g l^-1 day^-1, respectively. Results of the current study have demonstrated that combination of soybean meal and yeast extract as nitrogen source is beneficial for the production of red Monascus pigment by Monascus purpureus.

Conflict of interest: The authors declare no conflict of interest.

Background and objective: Continuous increases in poultry production have led to increases in slaughterhouse wastes and needs for control of these organic matter-rich wastes. Previously, burning and burial methods were used to control the wastes that contaminated the environment and spread diseases. Nowadays, hydrolysis of the waste proteins is an effective way to produce new added-value products and to control wastes. The aim of this study was to achieve optimal conditions for the enzymatic hydrolysis of the industrial wastes from poultry slaughterhouses.

Material and methods: To achieve the highest hydrolysis efficiency, an experimental design was used based on thesurface response methodology to assess optimum conditions of the hydrolysis reaction parameters. Factors, including temperature (50-70°C), pH (6.5-8.5) and enzyme to substrate ratio (1.5-5.5% (v w^-1)), were investigated at five levels using central composite design. Degree of the hydrolysis was considered as response.

Results and conclusion: Statistical analysis showed that the regression coefficient (R²) for the model included 0.9592, which indicated a high accuracy of the model to predict the reaction conditions with variables. The highest degree of hydrolysis was achieved as 12.78% at an enzyme/substrate ratio of 3.5%, pH of 7.5 and temperature of 60°C. Under optimized conditions, hydrolyzed proteins included molecular weights less than 14.5 kDa. Results have shown that enzymatic hydrolysis of the whole poultry slaughterhouse wastes is possible using alcalase as a protease enzyme.

Conflict of interest: The authors declare no conflict of interest.

Background and objective: Nowadays, anticancer effects of 2,6 dimethoxy benzoquinone are verified. Optimization of 2,6 dimethoxy benzoquinone content of fermented wheat germ extract was carried out by investigating effects of the various effective factors on wheat germ fermentation by Saccharomyces cerevisiae.

Material and methods: Effects of controlling concentration of dissolved oxygen in fermentation media were studied on 2,6 dimethoxy benzoquinone content of fermented wheat germ extract. To increase the quantity of 2,6 dimethoxy benzoquinone in fermented wheat germ extract, simultaneous effects of four effective variables including wheat germ particle size, agitation rate, dry materials to water ratio and yeast to wheat germ ratio at three levels were investigated using Taguchi statistical design. Then, effects of fermentation time and increased scale on the content of 2,6 dimethoxy benzoquinone of fermented wheat germ extract were assessed using bench-scale fermenter. Concentration 2,6 dimethoxy benzoquinone was assessed using HPLC. Molecular weight patterns of the fermented wheat germ extract proteins and total protein of fermented wheat germ extract were assessed using gel electrophoresis and Kjeldahl methods, respectively.

Results and conclusion: Control of dissolved oxygen concentration of the fermentation process decreased 2,6 dimethoxy benzoquinone content to 0.135 mg g^-1. Investigation effects of particle size of wheat germ, agitation rate, dry materials to water ratio and yeast to wheat germ ratio on 2,6 dimethoxy benzoquinone production showed that 2,6 dimethoxy benzoquinone concentration increased to 2.58 mg g^-1 (dry material), one of the top concentrations ever reported. Effects of fermentation time in bench-scale bioreactor showed that the highest quantity of production was achieved within 16 h. Study of the protein patterns and total protein of fermented wheat germ extract and comparisons between these values and commercial samples showed that production improvement of 2,6 dimethoxy benzoquinone did not include significant effects on quality and quantity of proteins of fermented wheat germ extract. Results of this study demonstrated that fermentation conditions could significantly affect 2,6 dimethoxy benzoquinone contents of fermented wheat germ extract.

Conflict of interest: The authors declare no conflict of interest.

Background and objective: Literature contains extensive researches on use of multiple emulsions in a variety of areas such as foods, pharmaceuticals, and health products. Water-in-oil-in water double emulsion (W₁/O/W₂) was used in the present study for entrapping Lactobacillus casei where balance in gastric system is under influence of probiotics release mechanism. Role of β-cyclodextrin emulsifier presented in the external aqueous phase of the test emulsion was explainable through emulsion characterization analyses (Fourier Transform Infrared spectroscopy, particles size distribution and Scanning Electron Microscopy). Cells viability was determined in terms of first-order kinetics and by applying the probability concept and survivability in gastric system was evaluated probabilistically using the exponential distribution.

Material and methods: Three different ratios of W₁/O:W₂ [40:60, 50:50, 60: 40] were used for preparing W₁/O/W₂ emulsions to encapsulate Lactobacillus casei into the inner phase with using β-cyclodextrin emulsifier. Dynamic light scattering was used for determination of emulsion particle size. Presence of the functional groups was detected using infrared spectroscopy and recording the relevant peaks in the region of 4000 to 400 cm^-1. The differential equation for first-order kinetic (dx/dt = kx) was used for the cells viability determination. Exponential probability distribution in terms of failure time (reflection of the cells not being able to be released) was also used in this study (f(t) = λe^-λt).

Results and conclusion: By preparation of gastric environment in terms of the bile salts and in a pH-controlled media, viability of the encapsulated cells was monitored and the following expression for the first-order rate constant was obtained for the test emulsions (k_(60:40) < k_(50:50) < k_(40:60)). Emulsification appears to be feasible industrially since the composition of the emulsions used for Lactobacillus casei entrapment was entirely edible.

Conflict of interest: The authors declare no conflict of interest.

Background and objective: Polyphenol oxidase enzyme catalyzes oxidation of o-diphenol to o-quinone using molecular oxygen, while the final product unacceptably includes brown pigments. Therefore, inhibition of polyphenol oxidase is essential for the preservation of food products and vegetables. The enzyme is clinically beneficial for the treatment of dermal disorders with links to unusual darkening of the skin (hyper pigmentation) and is helpful in development of skincare products. The present study describes characterization and inhibition kinetics of the polyphenol oxidase from Cinnamomum verum fruit coat.

Material and methods: Purification and quantification of polyphenoloxidase were carried out using (NH₄)₂SO₄ precipitation, dialysis with Sephadex G-100 column chromatography. The molecular weight was reported using SDS-PAGE. The Km and Vmax values were calculated using Lineweaver-Burk plot. The optimum pH, temperature and freeze-thaw were studied. Effects of several organic compounds on polyphenol oxidase activity were tested and IC₅₀ values were calculated.

Results and conclusion: Polyphenol oxidase of Cinnamomum verum fruit coat has partially been purified as nearly 3.75-fold with an improvement of 4.58% using catechol as the substrate. The enzyme showed a single band with a molecular weight of approximately 66 kD. Optimal pH and temperature included 6.0 and 37°C, respectively. The Km and Vmax values included 1.67 Mm and 64.57 ∆A min^-1, respectively. Inhibition type of cinnamic acid and ascorbic acid were uncompetitive while propyl benzoic acid showed a mixed type of inhibition. Thiol and chelating agents were strong inhibitors of enzyme activity. In conclusion, polyphenol oxidase can be used for the development of biosensors to detect and degrade phenolic compounds in industrial waste water.

Background and objective: Plant-based fermented foods containing favorable micro-organisms have been used to improve diets. Starter microorganisms may produce toxic compounds that are hazardous to consumers. Brine shrimp lethality test is a convenient and appropriate assay to check toxicity of samples. The aim of this study was to investigate toxicity of pasteurized coconut beverages at 70°C, 80°C and 90°C for 25, 15 and 5 min, respectively, and unpasteurized coconut beverages fermented by Lactococcus lactis against Artemia salina nauplii.

Material and methods: After extraction of coconut beverages fermented by Lactococcus lactis using methanol, cytotoxicity was assessed using (lethality concentration). Newly 10 hatched Artemia salina nauplii were transferred into various concentrations (in replicates) of the fermented sample extracts. After 24 h, survived Artemia salina nauplii were counted and lethality concentration was assessed. The brine shrimp lethality test was used to investigate sample toxicity at various doses from 1 to 500 µg ml^-1 at various time intervals.

Results and conclusion: The fermented extracts included low larvicidal potential against Artemia salina nauplii. Correlations were reported between the extract doses and percentage mortality of nauplli brine shrimp. The pasteurized fermented extracts were less toxic and cheaper. Interestingly, starter culture, fermentation, thermal treatment and time contributed to breaking down of hydrolysable tannins and larger polyphenolic compounds, producing smaller compounds with lower toxicity responses in brine shrimp lethality test. The four probiotics beverage extracts included non-cytotoxic activity as presented by low mortalities in brine shrimp lethality test. In conclusion, these extracts can be used to justify probiotic production of beverages.

Conflict of interest: The authors declare no conflict of interest.