Application of Poly(hydroxyalkanoate) In Food Packaging: Improvements by Nanotechnology

The environmental impact of plastic usage is of critical concern and too great to repair. A shift toward biodegradable food packaging is one option. The aim of this review paper is the study of the potential of biodegradable materials for food packaging. The main characteristics in relation to food usage can be narrowed down to mass transfer (gas and water vapor), thermal and mechanical properties. Among several kinds of biodegradable polymers, poly(hydroxyalkanoate) is one of the favorable candidates for food packaging due to its physical and mechanical properties, biodegradability, with low permeability for O2, H2O and CO2 without residues of catalysts and water solubility. The main focus of this article is to address poly(hydroxyalkanoate) as a potential candidate for food packaging. The need of applying biobased polymers in food packaging is presented in the introduction of this study. We also describe the most common biopolymers providing a brief overview of classification and application. This is followed by an outline of biopolymer production and a main section in which the properties of poly(hydroxybutyrate)-based nanocomposites of greatest relevance to food packaging are discussed. Furthermore, several approaches for improvement of poly(hydroxybutyrate) properties are described and the role of nanotechnology to improve its mechanical properties is presented. Finally, the article concludes with a summary as well as some possible future trends

The Effect of Homogenization Pressure and Stages on the Amounts of Lactic and Acetic Acids of Probiotic Yoghurt

Nowadays the use of probiotic products especially yogurt, due to having wonderful and health properties, has become popular in the world. In this study, the effect of homogenization pressure (100, 150 and 200 bars) and stage (single and two) on the amount of lactic and acetic acids was investigated. Yoghurts were manufactured from low-fat milk treated using high pressure homogenization at 100,150 and 200 bar and at 60°C. The amount of lactic and acetic acids was determined after the days 1, 7, 14 and 21 of storage at 4ºC. The experiments were set up using a completely randomized design. With the increase of pressure and stage of homogenization, the amount of both acids was increased (p<0.01). The greatest amount of lactic and acetic acids during the storage period was observed in the sample homogenized at a pressure of 200 bars and two stages

Alkaline protease production on date waste by an alkalophilic Bacillus sp. 2-5 isolated from soil

This research focused on isolation and characterization of a new strain of Bacillus sp. from alkaline soil, which was able to producing extracellular alkaline protease and amylase from date waste at pHranging from 8 to 11 and temperatures of 20 to 50°C. Purification was conducted by fractionation, concentration, and cation exchange chromatography. The yield and fold of enzyme purification was24% and 50 times, respectively. Molecular weight of purified enzyme was measured by SDS-PAGE as 24.7 kDa. Produced alkaline protease by Bacillus sp. 2 - 5 showed the most caseinolytic activity(without any gelatinolytic activity) at pH > 10. The highest protease activity was achieved in the following conditions: starch concentration (as carbon source) 0.5 g/L, yeast extract and casamino acid(as mixed nitrogen source) 0.5 and 0.3% (w/w), temperature of 45°C at pH 10.7 after 36 h. Based on the optimization studies of production and purification stages, specific and protease activity 143550APU/mg and 57420 APU/mL were achieve

Mycoprotein Production from Date Waste Using Fusarium venenatum in a Submerged Culture

Background and objective: Production of single cell protein has various outstanding advantages, e.g., it can be grown on waste and it is environmental friendly as it helps in upgrading agricultural wastes. In the present study, the influence of process parameters on the biomass formation (g l-1), protein production (% w w-1) and volumetric productivity (g l-1 h-1) of Fusarium venenatum IR372C was determined. Material and methods: The Vogel medium was used with glucose as the carbon source for pre culture cultivation and date sugar as the carbon source for production medium. In the first phase of the study, submerged fermentation was conducted in 500 ml flasks and a 3l stirred-tank bioreactor was exploited to conduct the submerged fermentation in the second phase. Plackett-Burman Design with eleven factors, i.e., date sugar concentration, NH4H2PO4, peptone, MgSO4, KH2PO4, temperature, time, shake rate, inoculate age, inoculate size, pH in two levels and Response Surface Methodology with three variables, i.e., date sugar concentration, time and inoculate size were employed to determine the fermentation condition by which the maximum biomass, protein and productivity were achieved. Results and conclusion: Based on obtained results, by using the selected levels of influencing process variables, a relatively high amount of total protein (ca. 4 g l-1, 65.3% in the first phase using flasks and 5.5 g l-1, 76% in the second phase by using the bioreactor, respectively) was achieved. The amino and fatty acid profiles of mycoprotein and its relatively high fiber content (6%) imply that mycoprotein could be incorporated in various types of foods as a functional ingredient. Conflict of interest All authors have declared that they don’t have any conflict of interest for publishing this research. &nbsp

Bioproduction of Conjugated Linoleic Acid in Yogurt by Probiotic Bacteria

Conjugated linoleic acid as unique fatty acid of milk fat has beneficial properties including antioxidant‚ anticarcinogen‚ antidiabetic‚ antiblood pressure‚ stimulating the body immune system and reducing cholesterol. The aim of this study was assessing ability of some probiotics for biotransformation of linoleic acid to conjugated linoleic acid. Effect of process variables were investigated on production of conjugated linoleic acid in probiotic yogurt. An 8 run Plackett-Burman design was used to study the effect of 7 variables included: addition of supplements (whey powder‚ the amount of added grape seed oil), fermentation (temperature, pH, incubation time) and inoculum condition (age and size) on biomass and conjugated linoleic acid production in probiotic yogurt containing strains of Lactobacillus acidophilus La5, Bifidobacterium bifidum and Propionibacterium freudenerchii grown in medium containing free linoleic acid. The highest amount of conjugated linoleic acid was obtained by addition of 8% w/v whey powder, addition of 4%v/v grape seed oil in pH=6.0, inoculation of 0.7%v/v Inoculum of 36 h age and fermentation at temperature of 35°C for 27 h. This research showed that at the optimized conditions‚ the amount of conjugated linoleic acid in probiotic yogurt was increased by 40% from an average of 8.01 mg/g fat in non-treated yogurt to 11.03 mg/g fat of probiotic yogurt containing grape seed oil

Application of zein antimicrobial edible film incorporating Zataria multiflora boiss essential oil for preservation of Iranian ultrafiltered Feta cheese

Zein based edible film was developed and incorporated with Zataria multiflora boiss essential oil. Mechanical and microbiological characteristics of this biofilms were measured. Increasing concentration of antimicrobial agent in film reduced stretchability, tensile strength and elongation, however increased the thickness and water vapor transmission parameters (P<0.05). Addition of Z. multiflora boiss essential oil, resulted in decreasing the count of viable Salmonella enteritidis, Listeria monocytogenes, Escherichia coli and Staphylococcus aureus in the produced cheese. This investigation concludes that the biofilm containing Z. multiflora boiss essential oil can be highly recommended for packaging of Feta cheese with the improved microbiological and sensory quality. Besides, application of natural plant essential oil has economical and health promoting benefits.Keywords: Zein, Zataria multiflora, cheese, pathogens, mechanical properties

Bench scale production of xanthan from date extract by Xanthomonas campestris in submerged fermentation using central composite design

In this research, xanthan production from date extract was done by using bacterium Xanthomonas campestris PTCC1473 in submerged fermentation (SmF). The impact of different initial concentrations of carbon (date extract) and nitrogen (NH4NO3) sources on cell growth and xanthan production was evaluated. Inoculum (72 h) from the YMB medium was added to the substrate with defined chemical components (nitrogen, sugar, moisture, ash and pH) and incubated. Central composite design (CCD) was used to evaluate the effects of carbon and nitrogen sources on production yield. The results indicate a decrease of cell growth in carbon source concentration up to 50 g/l. The highest cell growth and xanthan production were achieved at 40 g/l concentration of carbon source. The nitrogen source concentration did not cause a significant effect on cell growth; but the highest concentration of xanthan was produced in 0.2 g/l of nitrogen source. The ratio of carbon to nitrogen content had a significant impact on xanthan production. In the optimum condition, maximum concentration of produced xanthan yield and productivity was seen at 11.2 g/l and 8.19 g/kg.day, respectively.Key words: Xanthan, submerged fermentation, date extract, Xanthomonas campestris, central composite design

Exploration and Understanding of Beneficial Properties of Lactic Acid Bacteria: 10 years of experience in Applied Food Biotechnology

The scientific community is currently facing a more than exponential increase of knowledge in all areas and disciplines. In the last 10 years, the contribution of the journal Applied Food Biotechnology was eminent in distributing that knowledge by providing a tribune for researchers from different countries all over the world to share their ideas, observations, and hypotheses. With a focus on different aspects of applied and fundamental biological sciences, the journal Applied Food Biotechnology was established as a reference of the Iranian scientific community. In the last 10 years, the journal has been covering several topics related to exploring the beneficial properties of lactic acid bacteria (LAB) and their role in modern food technologies. LAB are already proven as a realization of Hippocrates' vision for the potential role of food in human and other animals' health. However, what will be the next frontier? What are the challenges in understanding the interactions between microbiota and host microorganisms? What will be the novel analytical tools, facilitating a new era of probiotic research? These were only a few research topics presented and discussed in Applied Food Biotechnology in the last decade. This editorial overview aims to celebrate the scientific contribution of Applied Food Biotechnology in the area of research associated with the beneficial properties of LAB, summarizing some of the studies published in the journal