applied food biotechnology
Volume:7 Issue: 4, Autumn 2020

Lactobacillus acidophilusATCC 4356 was used for oxalate degradation activity. In the present study, for the first time, the simultaneous influence of process variables on the analysis of high oxalate concentration and its optimization in the simulated intestinal environment was performed. In the end, the optimal results were performed in a tea environment as a common oxalate-containing beverage.

After screening the design of ten process variables including pH, glucose, sucrose, inulin, ammonium, sodium oxalate, yeast extract, sodium acetate, inoculum age, and size using Plackett-Burman design, a Box-Behnken method was used with four major variables of pH, glucose, sodium oxalate, and inulin.

Results showed that oxalate degradation in simulated rumen fluid was significantly affected by pH and sodium oxalate and glucose concentrations. At optimized conditions, oxalate degradation reached 48.94 ±0.98% of initial concentration. Furthermore, oxalate degradation was investigated in tea (as themost common hot drink in many countries such as Iran) at various times, temperature, and glucose concentration. At optimum condition, oxalate concentration reached 98.86% ±1.05 (from 264 to 24 mg per100 ml)

Astaxanthin is a keto-carotenoid pigment known as one of the most valuable compounds with great potentials in the market. It has widely been used in nutraceutical, pharmaceutical, cosmetics and food industries due to its strong antioxidant activity. Green microalgae seem as promising natural sources in production of astaxanthin. The aim of this study was to optimize astaxanthin production in Coelastrumsp. to overcome low productivity of microalgae.

This study was carried out using experimentally statistical technique and Taguchi method to find optimum conditions for maximizing production of astaxanthin in green microalgae, Coelastrumsp. Effects of nutritional (carbon and nitrogen) and environmental (light and salinity) factors on biomass and astaxanthin production were investigated. Experiments were carried out for light intensity (250-550 μmol photons m-2 s-1), salinity using sodiumchloride(1.0-3.0 g l-1), carbon source using sodium acetate (0.5-2.0 g l-1) and nitrogen source using sodium nitrate (0.1-0.3 g l-1)

Results showed that optimum conditions of astaxanthin production in Coelastrum sp. included 250 μmol photons m-2s-1 of light intensity, 3 g l-1salinity, 0.5 g l-1carbon and 0.1 g l-1nitrogen with a maximum yield of astaxanthin (14.44 mg l-1), which was 2-fold higher than that before optimization. This optimization resulted in high quantities of astaxanthin production using optimization of conditions that affected production yields ofastaxanthin from Coelastrumsp.

Survival of beneficial microorganisms in human gut faces many challenges. Immobilization on dietary fibers not only increases the viability of probiotic cultures, but also improves intestinal microbiota composition and decreases several diseases. Therefore, the objective of this study was to assess effects of wheat bran immobilization on survival of multiple species dairy starters under high acidity and bile saltsconditions.

Dairy starter association included lactic acid bacteria of Lactobacillus delbrueckii RKM 0850, Lactobacillus paracasei RKM 0852 and Lactobacillus.parabuchneri RKM 0854, acetic acid bacteria of Acetobacter syzygii RKM 0855, propionic acid bacteria of Propionibacterium freudenreichii subsp.shermanii PL and yeast of Kluyveromyces marxianusRKM 0853. Physical immobilization of the whole associationwas carried out using adsorption on 3% wheat bran.

Effects of acid and bile saltsstresses on microbial associationsurvival largely depended on the taxonomic affiliation, aeration rate and experiment media. Kluyveromyces marxianusRKM 0853 was highly resistant to pH 2.0-3.0 and addition of 0.5-15.0% of bile salts. Furthermore, Lactobacillus paracaseiRKM 0852 and Acetobacter syzygii RKM 0855 were the most resistant microorganisms to bile salts and Lactobacillus delbrueckiiRKM 0850 and Lactobacillus parabuchneri RKM 0854 included the best survival rates at low pH. Wheat bran immobilization promoted survival of the microbial associationunder stress conditions and prevented loss of viability by more sensitive species. These results are essential for understanding and improvement of stress tolerance in probiotic microorganisms of various taxonomies

 Arthrospira cyanobacteria are important freshwater blue-green microalgae as food protein sources for humans. Arthrospira maxima phototrophic cultivation was carried out under various minimum media formulations to enhance biomass and protein productions. Macronutrients and micronutrients are vital for biomass production and protein accumulation of Arthrospira maxima for food supplemented uses.

 Photoautotrophic cultivation of Arthrospira maxima IFRPD 1183 was carried out using various Zarrouk culture media and inoculum preparation conditions for biomass and protein productions. Arthrospira maxima IFRPD 1183 was cultivated using algal chamber under closed and open photobioreactor systems.

 Micronutrients of B6 solution; NH4VO3, K3Cr2 (SO4)4. 24H2O, NiSO4. 7H2O, Na2WO3, Co (NO3)2. 6H2O and Ti2 (SO4)3 did not affect cell growth and protein accumul-ation in absence of media for inoculum production. Inoculum preparation under various conditions of Arthrospira maxima IFRPD 1183 was studied using filtration of the old media before use (cell filtration inoculum) with no filtrations of the old media before use (cell non-filtration inoculum). Cell non-filtration inoculum preparation was reported appropriate for biomass production and protein accumulation. For large-scale productions, open pond system of Arthrospira maxima IFRPD 1183 resulted in maximum biomass and protein production at nearly 1 g l-1 and 64% (DW), respectively, for repeat batch photoautotrophic cultivation. Absence of micronutrients with cell non-filtration inoculum was reported as an easy process to achieve large biomass and protein productions for closed and open photoautotrophic cultivations of Arthrospira maxima at decreased costs.

Enzyme-assisted hydrolysis of the proteins from foodsources is an effective way to generate peptides with various bioactive properties. Furthermore, enzyme immobilization is a way to recycle enzymes for thefuture uses.The objective of this study was to investigate the effects of neutrase and thermolysin immobilization on the enzyme properties and in vitroanti-diabetic properties of intestinal digests achieved by the simulated digestion of egg white protein hydrolysates.

Neutrase and thermolysin were immobilized on cellulose-coated magnetite nanoparticles. Then, enzyme activity, thermal resistance, reusability and optimum conditions of the egg white protein hydrolysis were assessed. Egg white protein hydrolysates were then digested in vitroand inhibitory activities of the intestinal digests against dipeptidyl peptidase IV (DPP-IV) and α-glucosidase were investigated.

Enzymes immobilizationresulted in increasesin the thermal stabilities of them. Optimum temperatures for the egg white protein hydrolysis increased by 4.0 and 3.2 °Cfor neutrase and thermolysin, respectively.Digests from the hydrolysates of free neutrase effectively inhibited DPP-IV and α-glucosidase by 17.9 and 29.7%, respectively. These values for the hydrolysates released by the free thermolysin were higher (37.2 and 35.1%, respectively). The enzyme immobilization resulted in a 4.4% decrease in DPP-IV inhibitory activities of the digests for the hydrolysates from neutrase and a 28.6% decrease for those from thermolysin. Decreases in α-glucosidase inhibition due to the immobilization included 9.8% for neutrase and 12.2% for thermolysin for the digests from the hydrolysates. Based on the results from the current study, hydrolysates from the egg white proteins achieved by the free and immobilized neutrase and thermolysin can be used in formulations of the functional foods and nutraceuticals with multifunctional properties.

Diabetes mellitus is the fifth leading cause of death in the world. Damaging effects of diabetes include advanced metabolic complications and various organ lesions. More than 90% of diabetic cases belong to type 2 diabetes. For decades, medicinal fungi such as Trametes versicolorhave been considered as treatments for diabetes. The fungi exopolysaccharides show α-glucosidase activity in the intestinal membrane.

In this study, Iranian Trametes versicolorwas cultured in various media based on soy milk, cow milk and soy protein extraction. After selecting appropriate culture media for biomass and exopolysaccharide production, response surface method with Box-Behnken design was used to investigate effects of independent variables of glucose (g l-1), soy milk (v v-1) and pH on biomass and exopolysaccharide production and optimization of these products. An animal (rat) model of streptozotocin-induced diabetic rats was used to investigate effects of exopolysaccharides on diabetes.Rats were treated with exopolysaccharides for 21 days.

Results showed that the culture media containing soy milk was appropriate for the growth and production of fungal products. Productions of biomass and exopolysaccharides increased to 2.87 gl-1 and 1.37 g l-1 respectively. Based on the analysis of response surface method, pH with p-value of 0.0004 and pH and soybean interaction with p-value of 0.0129 included significant effects on exopolysaccharide production. In optimum condition of the culture media with pH 4.67, 13.01 g l-1 glucose and 75% v v-1 soybean milk, biomass and exopolysaccharides reached 21.80 g l-1 and 9.6 g l-1. In diabetic rat model treated with exopolysaccharides, a 50.38% decrease in blood glucose was seen while triglycerides, cholesterol and low-density lipoproteins included 89, 20 and 21.67%, respectively. Furthermore, high-density lipoproteins increased by nearly 5.12%.

Fish tissue and liver and some microalgae are some of the richest sources of omega-3 (ω3) fatty acids in nature. Annually, more than 4.2 billion tons of algae are cultivated with various goals. Therefore, development of novel ways to extract more ω3-fatty acids from microalgal tissues is a valuable target. In this study, comparisons were carried out between various methods of extraction and purification of ω3-fatty acids from a native species of microalgae.

Combination method (urea complex and winterization) used as a method for extraction of ω3-fatty acids. For the optimization of combination method, three factors, including temperature of winterization, time of winterization and frequency of extraction with hexane were studied at fourvarious levels and 15 examinations using Design Expert 10.0 software.

Results of optimization included 10 h for time of winterization, -20 °C for temperature of winterization and six times of extraction with hexane. In optimized conditions, the highest quantity of ω3-fatty acids derived from Chlorella vulgaris at the moisture of 65% was 43.6 mg g-1fatty acids.