Biosorption of cadmium from aqueous solution by combination of microorganisms and chitosan: response surface methodology for optimization of removal conditions.

The food-grade adsorbents of Saccharomyces cerevisiae (108 CFU/mL), Bifidobacterium longum (108 CFU/mL) and chitosan (1%w/v) alone or in combination were used for biosorption of cadmium (Cd) from aqueous solution. Among the tested adsorbents, combination of B. longum and chitosan had the highest efficiency. Therefore, biosorption process with B. longum/chitosan as the most efficient biosorbent was optimized by variables of pH (3-6), temperature (4-37 °C), contact time (5-180 min) and Cd concentrations (0.01-5 mg/L) using RSM. Twenty-seven tests were carried out and the data fitted to the second-order polynomial models. Results revealed that 99.11% of Cd was reduced within 180 min at concentration of 2.5 mg/L, pH 6 and temperature of 20.5 °C that were considered as the optimal conditions for Cd removal. The trend of isotherm was more fitted to the Langmuir model and maximum biosorption capacity was obtained about 3.61 mg/g. The pseudo-second-order fitted the biosorption kinetics for Cd ions. The B. longum/chitosan biosorbent exhibited the high affinity to Cd ion in the presence of coexisting metal ions. It could remove 81.18% of Cd from simulated gastrointestinal tract. Thus, B. longum/chitosan can have good potential as an effective adsorbent for Cd biosorption from aqueous solutions and human body.

A comprehensive review on yogurt syneresis: effect of processing conditions and added additives.

Yogurt, produced by the lactic fermentation of milk base, is an important dairy product worldwide. One of the essential sensory properties of yogurt is the texture, and some textural defects such as weak gel firmness and syneresis likely occur in various types of yogurts, affecting consumer acceptance. In this regard, various strategies such as enrichment of milk-based with different additives and ingredients such as protein-based components (skimmed milk powder (SMP), whey protein-based powders (WP), casein-based powders (CP), and suitable stabilizers, as well as modification of processing conditions (homogenization, fermentation, and cooling), can be applied in order to reduce syneresis. The most effective proteins and stabilizers in syneresis reduction are CP and gelatin, respectively. Furthermore, yogurt's water holding capacity and syneresis can be affected by the type of starter cultures, the protolithic activity, production of extracellular polysaccharides, and inoculation rate. Moreover, optimizing the heat treatment process (85 °C/30 min and 95 °C/5 min), homogenization (single or dual-stage), incubation temperature (around 40 °C), and two-step cooling process can decrease yogurt syneresis. This review is aimed to investigate the effect of fortification of the milk base with various additives and optimization of process conditions on improving texture and preventing syneresis in yogurt.

Co-encapsulation of omega-3 and vitamin D3 in beeswax solid lipid nanoparticles to evaluate physicochemical and in vitro release properties.

In recent years, lipophilic bioactive compounds have gained much attention due to their wide range of health-benefiting effects. However, their low solubility and susceptibility to harsh conditions such as high temperatures and oxidation stress have limited their potential application for the development of functional foods and nutraceutical products in the food industry. Nanoencapsulation can help to improve the stability of hydrophobic bioactive compounds and protect these sensitive compounds during food processing conditions, thus overcoming the limitation of their pure use in food products. The objective of this work was to co-entrap vitamin D3 (VD3) and omega 3 (ω3) as hydrophobic bioactive compounds providing significant health benefits in beeswax solid lipid nanoparticles (BW. SLNs) for the first time and to investigate the effect of different concentrations of VD3 (5 and 10 mg/mL) and ω3 (8 and 10 mg) on encapsulation efficiency (EE). Our findings revealed that the highest EE was obtained for VD3 and ω3 at concentrations of 5 mg/mL and 10 mg, respectively. VD3/ω3 loaded BW. SLNs (VD3/ω3-BW. SLNs) were prepared with zeta potential and size of-32 mV and 63.5 nm, respectively. Results obtained by in-vitro release study indicated that VD3 release was lower compared to ω3 in the buffer solution. VD3 and ω3 incorporated in BW. SLNs demonstrated excellent stability under alkaline and acidic conditions. At highly oxidizing conditions, 96.2 and 90.4% of entrapped VD3 and ω3 remained stable in nanoparticles. Moreover, nanoparticles were stable during 1 month of storage, and no aggregation was observed. In conclusion, co-loaded VD3 and ω3 in BW. SLNs have the great potential to be used as bioactive compounds in food fortification and production of functional foods.

Dual COX-2/15-LOX inhibitors: A new avenue in the prevention of cancer.

Dual cyclooxygenase 2/15-lipoxygenase inhibitors constitute a valuable alternative to classical non-steroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 (cyclooxygenase-2) inhibitors for the treatment of inflammatory diseases, as well as preventing the cancer. Indeed, these latter present diverse side effects, which are reduced or absent in dual-acting agents. In this review, COX-2 and 15-LOX (15-lipoxygenase) pathways are first described in order to highlight the therapeutic interest of designing such compounds. Various structural families of dual inhibitors are illustrated. This study discloses various structural families of dual 15-LOX/COX-2 inhibitors, thus pave the way to design potentially-active anticancer agents with balanced dual inhibition of these enzymes.

Encapsulation of Heracleum persicum essential oil in chitosan nanoparticles and its application in yogurt.

Heracleum percicum essential oil (HEO) at various levels was encapsulated in chitosan nanoparticles and its potential application in yogurt was investigated. The values obtained for encapsulation efficiency, loading capacity, mean particle size, and zeta potential of nanoparticles were 39.12-70.22%, 9.14-14.26%, 201.23-336.17 nm, and + 20.19-46.37 mV, respectively. The nanoparticles had spherical shape with some holes as a result of drying process. In vitro release studies in acidic solution and phosphate buffer solution indicated an initial burst effect followed by slow release with higher release rate in acidic medium. Results of antibacterial activity revealed that Staphylococcus aureus and Salmonella typhimurium with inhibition zones of 21.04-38.10 and 9.39-20.56 mm were the most sensitive and resistant bacteria to HEO, respectively. Incorporation of encapsulated HEO into yogurt decreased pH and increased titratable acidity due to stimulation of starters' activity. Interaction of nanoparticles with proteins decreased syneresis in yogurt. Regarding antioxidant activity, a higher value was observed in yogurt containing encapsulated HEO after 14 days of storage due to degradation and release of essential oil from nanoparticles. In conclusion, application of HEO nanoparticles in yogurt could be a promising approach for development of functional food products such as yogurt with enhanced antioxidant properties.

An Overview of Antimicrobial Activity of Lysozyme and Its Functionality in Cheese.

Due to the concern of consumers about the presence of synthetic preservatives, researchers and food manufacturers have recently conducted extensive research on the limited use of these preservatives and the introduction and use of natural preservatives, such as herbal extracts and essential oils, bacteriocins, and antimicrobial enzymes. Lysozyme is a natural enzyme with antimicrobial activity that has attracted considerable attention to be potentially utilized in various industries. Since lysozyme is an intrinsic component of the human immune system and has low toxicity; it could be considered as a natural antimicrobial agent for use in food and pharmaceutical industries. Lysozyme exerts antimicrobial activity against microorganisms, especially Gram-positive bacteria, by hydrolyzing 1,4-beta-linkages between N-acetylmuramic acid and N-acetylglucosamine in the cell wall. In addition, increased antimicrobial activity of lysozyme against Gram-negative bacteria could be achieved by the modification of lysozyme through physical or chemical interactions. Lysozyme is presented as a natural preservative in mammalian milk and can be utilized as a bio-preservative in dairy products, such as cheese. Both bacteria and fungi can contaminate and spoil the cheese; especially the one that is made traditionally by raw milk. Furthermore, uncontrolled and improper processes and post-pasteurization contamination can participate in the cheese contamination. Therefore, besides common preservative strategies applied in cheese production, lysozyme could be utilized alone or in combination with other preservative strategies to improve the safety of cheese. Hence, this study aimed to review the antimicrobial properties of lysozyme as natural antimicrobial enzyme and its functionality in cheese.

The assessment of lead concentration in raw milk collected from some major dairy farms in Iran and evaluation of associated health risk.

Milk is one of the most consumed sources among people, especially children. hence, its contamination with heavy metals can pose a serious risk to children. Therefore, this study aimed to measure the lead concentration as one of the most dangerous heavy metals in the raw milk of several major animal husbandries in Tehran province from Iran. A total of 57 raw milk samples were collected from different regions of Tehran province. The lead contents were measured using a graphite furnace atomic absorption spectrometer. To evaluate the risk of the samples and hazard quotient (HQ) were calculated. The results showed that HQ for all samples was lower than 1 which was found within the acceptable level. Because the absorption of Pb is higher in children and this metal has a cumulative property in the body, even its small weekly intake can be dangerous in long-term consumption.

Antibacterial Activity of Pediocin and Pediocin-Producing Bacteria Against Listeria monocytogenes in Meat Products.

One of the most important challenges in the food industry is to produce healthy and safe food products, and this could be achieved through various processes as well as the use of different additives, especially chemical preservatives. However, consumer awareness and concern about chemical preservatives have led researchers to focus on the use of natural antimicrobial compounds such as bacteriocins. Pediocins, which belong to subclass IIa of bacteriocin characterized as small unmodified peptides with a low molecular weight (2.7-17 kDa), are produced by some of the Pediococcus bacteria. Pediocin and pediocin-like bacteriocins exert a broad spectrum of antimicrobial activity against Gram-positive bacteria, especially against pathogenic bacteria, such as Listeria monocytogenes through formation of pores in the cytoplasmic membrane and cell membrane dysfunction. Pediocins are sensitive to most protease enzymes such as papain, pepsin, and trypsin; however, they keep their antimicrobial activity during heat treatment, at low temperatures even at -80°C, and after treatment with lipase, lysozyme, phospholipase C, DNase, or RNase. Due to the anti-listeria activity of pediocin on the one hand and the potential health hazards associated with consumption of meat products on the other hand, this review aimed to investigate the possible application of pediocin in preservation of meat and meat products against L. monocytogenes.

Yeast cells for encapsulation of bioactive compounds in food products: A review.

Nowadays bioactive compounds have gained great attention in food and drug industries owing to their health aspects as well as antimicrobial and antioxidant attributes. Nevertheless, their bioavailability, bioactivity, and stability can be affected in different conditions and during storage. In addition, some bioactive compounds have undesirable flavor that restrict their application especially at high dosage in food products. Therefore, food industry needs to find novel techniques to overcome these problems. Microencapsulation is a technique, which can fulfill the mentioned requirements. Also, there are many wall materials for use in encapsulation procedure such as proteins, carbohydrates, lipids, and various kinds of polymers. The utilization of food-grade and safe carriers have attracted great interest for encapsulation of food ingredients. Yeast cells are known as a novel carrier for microencapsulation of bioactive compounds with benefits such as controlled release, protection of core substances without a significant effect on sensory properties of food products. Saccharomyces cerevisiae was abundantly used as a suitable carrier for food ingredients. Whole cells as well as cell particles like cell wall and plasma membrane can act as a wall material in encapsulation process. Compared to other wall materials, yeast cells are biodegradable, have better protection for bioactive compounds and the process of microencapsulation by them is relatively simple. The encapsulation efficiency can be improved by applying some pretreatments of yeast cells. In this article, the potential application of yeast cells as an encapsulating material for encapsulation of bioactive compounds is reviewed.

Salt content of processed foods in the Islamic Republic of Iran, and compliance with salt standards.

BACKGROUND: The World Health Organization recommends a maximum daily salt intake of 5 g for adults; the Islamic Republic of Iran has national standards for salt content of foods. AIMS: This study aimed to determine the salt content of industrial (made in large-scale food companies) and non-industrial (made in local stores using traditional methods) foods in Tehran province and compare it with the Iranian national standards. METHODS: We determined the salt content of 555 industrial and non-industrial products from parts of Tehran province in 2016 and 2018. The types of foods examined were: canned vegetables, industrial and non-industrial pickled vegetables, industrial and non-industrial tomato paste/tomato sauce, industrial and non-industrial nuts, and non-industrial barberry juice. The salt content of each product and its compliance with Iranian national standards was evaluated. RESULTS: The salt content of industrial tomato paste/sauce in 2016 (2.05 g/100 g) and non-industrial tomato paste/sauce in 2018 (2.37 g/100 g) was higher than the Iranian standard (1.5/2.0 g/100 g). The mean salt content of both industrial (1.97 g/100 g) and non-industrial (2.16 g/100 g) nuts was higher than the Iranian standard (1.88 g/100 g), as was the mean salt content of non-industrial juice (0.79 g/100 mL versus 0.25 g/100 mL). In 2018, only 48% and 40% of industrial and non-industrial tomato pastes/sauces met the Iranian standard. Overall, industrial products conformed better with the national standard than non-industrial products. CONCLUSIONS: Efforts are needed to reduce the salt content of processed food in the Islamic Republic of Iran and ensure they meet the Iranian standards.

Effective removal of lead (II) using chitosan and microbial adsorbents: Response surface methodology (RSM).

The ability of chitosan (1% w/v), Bifidobacterium longum (108 CFU mL-1) and Saccharomyces cerevisiae (108 CFU mL-1) separately or in combination (chitosan/B. longum, chitosan/S. cerevisiae, B. longum/S. cerevisiae) was assessed for lead (II) removal from aqueous solutions. The results showed chitosan/B. longum adsorbent had higher adsorption percentage in comparison with other adsorbents (p < 0.05). It was selected as the most efficient adsorbent and the effect of process variables including initial metal concentration (0.01-5 mg L-1), contact time (5-180 min), temperature (4-37 °C) and pH (3-6) on the its removal efficiency was evaluated with a Box-Behnken design. Twenty-seven test runs were performed and the optimal conditions for metal adsorption was observed at metal concentration of 2.5 mg L-1, contact time of 180 min, temperature of 37 °C and pH 4.5. The maximum lead (II) adsorption yield under optimal conditions was 97.6%. The foreign ions didn't diminish lead (II) adsorption by chitosan/B. longum and it had high selectivity toward the lead (II). Adsorption behavior was analyzed using the Freundlich and the Langmuir isotherms. The correlation coefficients (R2) demonstrated the Langmuir model had a better description on metal adsorption process. Overall, isotherms revealed chemisorption and physisorption were probably involved in metal adsorption on adsorbent.

Development, characterization and in vitro antioxidant activity of chitosan-coated alginate microcapsules entrapping Viola odorata Linn. extract.

Viola odorata Linn or sweet violet has several biological activities due to the presence of flavonoids, tannins, alaloid, glycoside, and saponins. However, susceptibility of these compounds to harsh conditions and low solubility is a great challenge for their incorporation into food products. Therefore, encapsulation can be an effective approach in this respect. In the present study, chitosan-coated microcapsules loaded with Viola extract were prepared for the first time and the effects of independent variables (sodium alginate: 1-1.5%, calcium chloride: 0.6-1.5% and extract concentrations: 5-10%) on encapsulation efficiency (EE%) were investigated. After evaluation of the model, the optimum condition for preparation of microcapsules was selected as 1.47% sodium alginate, 5.02% extract and 1.42% CaCl2 with EE% of 83.21%. The microcapsules developed at this condition had an acceptable spherical shape and the results obtained in Fourier transform-infrared spectroscopy (FTIR) indicated the presence of the extract within the microcapsules. The mean diameters of the uncoated and chitosan-coated microcapsules were 73 and 141 µm, respectively. The in vitro release in acidic medium (pH 1.5) and phosphate buffer saline (pH 7) were 43.21% and 95.39%, respectively. The prepared extract-loaded microcapsules have potential to be used in food products providing acceptable antioxidant activity.