Chitosan and mint mixture: A new preservative for meat and meat products

Green conversion of agroindustrial wastes into chitin and chitosan by Rhizopus arrhizus and Cunninghamella elegans strains

This article sets out a method for producing chitin and chitosan by Cunninghamella elegans and Rhizopus arrhizus strains using a green metabolic conversion of agroindustrial wastes (corn steep liquor and molasses). The physicochemical characteristics of the biopolymers and antimicrobial activity are described. Chitin and chitosan were extracted by alkali-acid treatment, and characterized by infrared spectroscopy, viscosity and X-ray diffraction. The effectiveness of chitosan from C. elegans and R. arrhizus in inhibiting the growth of Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica, Escherichia coli and Yersinia enterocolitica were evaluated by determining the minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC). The highest production of biomass (24.60 g/L), chitin (83.20 mg/g) and chitosan (49.31 mg/g) was obtained by R. arrhizus. Chitin and chitosan from both fungi showed a similar degree of deacetylation, respectively of 25% and 82%, crystallinity indices of 33.80% and 32.80% for chitin, and 20.30% and 17.80% for chitosan. Both chitin and chitosan presented similar viscosimetry of 3.79–3.40 cP and low molecular weight of 5.08 × 10³ and 4.68 × 10³ g/mol. They both showed identical MIC and MBC for all bacteria assayed. These results suggest that: agricultural wastes can be produced in an environmentally friendly way; chitin and chitosan can be produced economically; and that chitosan has antimicrobial potential against pathogenic bacteria.

Effects of chitosan, aqueous extract of ginger, onion and garlic on quality and shelf life of stewed-pork during refrigerated storage

Effects of 1% or 0.5% chitosan (CHI), 10% or 5% aqueous extract of ginger, onion and garlic (GOG) and their composite solutions (1% CHI+10% GOG, 0.5% CHI+5% GOG) on quality and shelf life of stewed-pork were evaluated. Microbiological (total bacterial count), chemical (pH, total volatile basic nitrogen (TVB-N), peroxide value (POV), 2-thiobarbituric acid (TBA)) and sensory characteristics were analysed periodically during refrigerated storage at 4 °C for 12 days. CHI and/or GOG treatments retarded the increases in pH, TVB-N, POV, TBA and total bacterial count. CHI showed better antibacteria but weaker antioxidation than GOG. Composite treatment had possible synergistic effect while the high concentration of composite solution (Mix1) had adverse effect on odour and overall acceptance. Mix2, the diluted solution of Mix1, could be a natural promising preservative for the stewed-pork considering the comprehensive effects of antioxidation, antibacteria and sensory quality, which could extend the shelf life for about 5-6 days.

Trends in the utilization of food additives

The frequent media reports on food additives weakened consumers’ trust in food producers and food control authorities as well. Furthermore, consumers’ uncertainty is also raised by the fact that they obtain their information from inadequate, mistrustful sources and, therefore, consumers might avoid the consumption of certain foodstuffs. While food producers may react by replacing artificial components by natural ones, they try to emphasize the favourable characteristics of their products. The authors describe the main trends and efforts related to food additives. On the basis of the overview it can be concluded that – besides taking into consideration consumers’ needs – product development and research directions are promising. Food producers’ efforts may help to restore consumer confidence and trust and they may help them to have informed choice. Orv. Hetil., 154(46), 1813–1819.

Antioxidant and Antimicrobial Properties of Chitosan-PE Bi-Layer Films by Incorporating Oregano Essential Oil

Chitosan-PE bi-layer films exhibit antimicrobial activity but poor antioxidant activity. Oregano essential oil (100μL/100mL) was incorporated into chitosan solution to improve films antioxidant and antimicrobial behaviors. The present work investigated the scavenging of O2·, ·OH, DPPH radical and reducing power of film, antimicrobial activity was also evaluated. The results showed that the scavenging effect of film solution on O2·, ·OH, and DPPH was 80.87%, 85.56%, and 87.24%, respectively. Reducing power of film increased with the improvement of oregano essential oil. The antibacterial activity againstE. ColiandB. Subtilisincreased from 80.77% to 96.15% and from 93.02% to 98.10%, respectively. The preservation experiments showed that chitosan-PE film incorporated with oregano essential oil could extend the shelf life of pork to 810 days at 4°C.

The effect of active ingredient-containing chitosan/polycaprolactone nonwoven mat on wound healing: in vitro and in vivo studies

The use of an electrospun polycaprolactone (PCL) nonwoven mat that is coated with a layer of chitosan (CS) containing active ingredient [tea tree oil (TTO)] represents an effective strategy for producing functional dressings. CS-coated porous PCL nonwoven mat (CS3/PCLNM) with various concentrations of active ingredients were produced and investigated. In vitro, active ingredient-containing CS3/PCLNM is effective in inhibiting the formation of nitrite and the growth of Staphylococcus aureus. Both active ingredient TTO and CS have been proven to reach their maximum amount of releases within 24 h of contact with water-based environment. In vivo, full-thickness skin removal (1.2 cm × 1.2 cm) was performed on the back of the C57BL6/J mice in noninfected and infected animal models. Four groups of functional dressings were tested in this work including Tegderm™, PCLNM, CS3/PCLNM, and 100 μL TTO-CS3/PCLNM. After 7 days post-treatment, the bacterial levels were found to be significantly lower in both CS3/PCLNM and 100 μL TTO-CS3/PCLNM-treated groups than in the control group (81.6 ± 18.1% and 93.7 ± 9.57% of reductions in the bacterial load in the pus relative to the control group, respectively). Additionally, based on the histological analyses, the 100 μL TTO-CS3/PCLNM-treated group outperformed all other groups in wound healing.

Heavy metals in spices and herbs from wholesale markets in Malaysia

As, Cd, Pb and Hg were analysed in commonly consumed spices and herbs in Malaysia. The range of As, Cd, Pb and Hg content was 0.24-2.54, 0.23-8.07, 1.54-8.94 and 0.06-0.52 µg g(-1), respectively. The highest concentration of Cd, Pb and Hg in spices and herbs exceeded the maximum permitted proportion, which are 1, 2 and 0.05 µg g(-1), respectively. This study suggests further monitoring of Cd, Pb and Hg on daily consumption of spices and herbs and its toxicological implication for consumers since only the amount of As was lower than the permitted concentration.

Chitosan dipping or oregano oil treatments, singly or combined on modified atmosphere packaged chicken breast meat

The present study examined the effect of natural antimicrobials: chitosan, oregano and their combination, on the shelf-life of modified atmosphere packaged chicken breast meat stored at 4°C. Treatments examined in the present study were the following: M (control samples stored under modified atmosphere packaging), M-O (samples treated with oregano oil 0.25% v/w, stored under MAP), M-CH (samples treated with chitosan 1.5% w/v, stored under MAP) and M-CH-O (treated with chitosan 1.5% w/v and oregano oil 0.25% v/w, stored under MAP). Treatment, M-CH-O, significantly affected mesophilic Total Plate Counts (TPC), lactic acid bacteria (LAB), Brochothrix thermosphacta, Enterobacteriaceae, Pseudomonas spp., and yeasts-moulds during the storage period. Lipid oxidation (as determined by MDA values) of control and treated chicken samples was in general low and below 0.5 mg MDA/kg, showing no oxidative rancidity during the storage period. Addition of chitosan to the chicken samples produced higher (P<0.05) lightness (L*) values as compared to the control samples. The results of this study indicate that the shelf-life of chicken fillets can be extended using, either oregano oil singly, and/or chitosan, by approximately 6 (M-O) and >15 (M-CH and M-CH-O) days. Interestingly, chitosan (M-CH) or chitosan-oregano (M-CH-O) treated chicken samples were sensorially acceptable during the entire refrigerated storage period of 21 days. It is noteworthy that the presence of chitosan in M-CH and M-CH-O samples did not negatively influence the taste of chicken samples, with M-CH samples receiving a higher score (compared to M-CH-O), probably as a result of a distinct and "spicy" lemon taste of chitosan, that was well received by the panelists. Based primarily on sensory data (taste attribute) M-CH and M-O treatments extended the shelf-life of chicken fillets by 6 days, while M-CH-O treatment resulted in a product with a shelf-life of 14 days, maintaining acceptable sensory characteristics.

Pressurized hot ethanol extraction of carotenoids from carrot by-products

Carotenoids are known for their antioxidant activity and health promoting effects. One of the richest sources of carotenoids are carrots. However, about 25% of the annual production is regarded as by-products due to strict market policies. The aim of this study was to extract carotenoids from those by-products. Conventional carotenoid extraction methods require the use of organic solvents, which are costly, environmentally hazardous, and require expensive disposal procedures. Pressurized liquid extraction (PLE) utilizes conventional solvents at elevated temperatures and pressure, and it requires less solvent and shorter extraction times. The extraction solvent of choice in this study was ethanol, which is a solvent generally recognized as safe (GRAS). The extraction procedure was optimized by varying the extraction time (2-10 min) and the temperature (60-180 °C). β-Carotene was used as an indicator for carotenoids content in the carrots. The results showed that time and temperatures of extraction have significant effect on the yield of carotenoids. Increasing the flush volume during extraction did not improve the extractability of carotenoids, indicating that the extrication method was mainly desorption/diffusion controlled. Use of a dispersing agent that absorbs the moisture content was important for the efficiency of extraction. Analysing the content of β-carotene at the different length of extraction cycles showed that about 80% was recovered after around 20 min of extraction.

Effect of alternative preservatives on the microbial quality, lipid stability and sensory evaluation of boerewors

Boerewors is a South African fresh sausage preserved with 450mg/kg sulphur dioxide (SO(2)). The preservative effects of rosemary (Ros; 260mg/kg) and chitosan (Chi; 10g/kg) were compared to SO(2). Eight boerewors models were formulated. Microbial, colour, lipid and sensory characteristics were evaluated. Chi and Chi in combination with other preservatives had a significant effect on reducing total bacterial, coliform and Enterobacteriaceae counts, comparable to SO(2). Chi, however, had a better effect on decreasing yeasts and mould counts than SO(2). Chi showed good colour properties comparable to SO(2). Ros showed comparable lipid stability to SO(2) but better when compared to Chi. Ros had a better effect on the sensory taste when compared to Chi, but SO(2) was still preferred. Reduced levels of 100mg/kg SO(2) showed good antimicrobial and colour effects in combination with Chi and in combination with Ros as antioxidant and improving the sensory properties. Alternative preservatives can be used to reduce the SO(2) content of boerewors.

Effect of chitosan coating enriched with thyme oil on postharvest quality and shelf life of shiitake mushroom (Lentinus edodes)

The effect of chitosan-oil coating on the postharvest quality and shelf life of shiitake (Lentinus edodes) mushrooms stored at 4 ± 1 °C for 16 days was investigated. Mushroom weight loss, firmness, total phenolics, ascorbic acid, malondialdehyde (MDA), electrolyte leakage rate, and microbial and sensory quality were measured. The results indicate that treatment with chitosan-oil coating maintained tissue firmness, inhibited increase of respiration rate, and reduced microorganism counts, such as yeasts and molds and pseudomonad, compared to control treatment. The efficiency was better than that of thyme oil treatment or chitosan coating. Furthermore, shiitake mushrooms treated with chitosan-oil coating also exhibited significantly higher levels of total phenolics, flavonoids, as well as individual phenolic compounds than control. Sensory evaluation proved the efficacy of chitosan-oil coating by maintaining the overall quality of shiitake mushroom during the storage period. Our study suggests that chitosan-oil coating might be a promising candidate for maintaining shiitake mushroom quality and extending their postharvest life.

Effect of distillation waste water and plant hormones on spearmint growth and composition

BACKGROUND

Distillation waste water (DWW) is a by-product from steam distillation of essential-oil crops; and currently, it is discharged into streams and rivers. The effects of DWW from 13 essential-oil crops, extracts from two alkaloid-containing species, and three plant hormones (methyl jasmonate, MJ; gibberellic acid, GA3; and salicylic acid, SA) were evaluated on productivity, essential-oil content and composition of spearmint (Mentha spicata L.) cv. 'Native'.

RESULTS

Spearmint plant height was increased by the application of GA3 and Melissa officinalis DWW but suppressed by the application of Rosmarinus officinalis and Tagetes lucida DWW. Generally, MJ, GA3 and M. officinalis and Mentha arvensis DWW increased dry yields. The concentration of L-carvone in the oil ranged from 550 g kg(-1) (with Monarda citriodora DWW) to 670 g kg(-1) (with T. lucida DWW). M. citriodora DWW reduced the concentration of L-carvone in the oil by 23% relative to the control.

CONCLUSION

Results suggest that DWW from essential-oil crops may affect monoterpene synthesis in M. spicata and, hence, may have a direct effect on the essential oil composition. DWW from essential-oil crops may be used as a growth promoter and modifier of the essential oil composition of spearmint.

Antioxidant activity of bovine and porcine meat treated with extracts from edible lotus (Nelumbo nucifera) rhizome knot and leaf

Lotus (Nelumbo nucifera) is an extensively cultivated vegetable in eastern Asia, particularly in China. Both lotus rhizome knot (LRK) and lotus leaf (LL) are waste products of the lotus industry. Extracts from LRK and LL are proposed as antioxidants for meat. Porcine and bovine ground meat samples were subjected to three treatments: CONTROL (with no additives), LRK (lotus rhizomes knot extract 3% w/w), and LL (lotus leaf extract 3% w/w). Raw and cooked samples were stored at 4°C and the antioxidant activity was determined at 1, 3, 6 and 10 days. Antioxidant activity was significantly increased in all meat samples with the addition of both LRK and LL, but LRK was more effective against lipid oxidation. The results show the potential for using LRK and LL extracts in the meat industry to prolong shelf life.

Review of antimicrobial and antioxidative activities of chitosans in food

Interest in chitosan, a biodegradable, nontoxic, non-antigenic, and biocompatible biopolymer isolated from shellfish, arises from the fact that chitosans are reported to exhibit numerous health-related beneficial effects, including strong antimicrobial and antioxidative activities in foods. The extraordinary interest in the chemistry and application in agriculture, horticulture, environmental science, industry, microbiology, and medicine is attested by about 17,000 citations on this subject in the Scopus database. A special need exists to develop a better understanding of the role of chitosans in ameliorating foodborne illness. To contribute to this effort, this overview surveys and interprets our present knowledge of the chemistry and antimicrobial activities of chitosan in solution, as powders, and in edible films and coating against foodborne pathogens, spoilage bacteria, and pathogenic viruses and fungi in several food categories. These include produce, fruit juices, eggs and dairy, cereal, meat, and seafood products. Also covered are antimicrobial activities of chemically modified and nanochitosans, therapeutic properties, and possible mechanisms of the antimicrobial, antioxidative, and metal chelating effects. Further research is suggested in each of these categories. The widely scattered data on the multifaceted aspects of chitosan microbiology, summarized in the text and in 10 tables and 8 representative figures, suggest that low-molecular-weight chitosans at a pH below 6.0 presents optimal conditions for achieving desirable antimicrobial and antioxidative-preservative effects in liquid and solid foods. We are very hopeful that the described findings will be a valuable record and resource for further progress to improve microbial food safety and food quality.

Advances in ingredient and processing systems for meat and meat products

Changes in consumer demand of meat products as well as increased global competition are causing an unprecedented spur in processing and ingredient system developments within the meat manufacturing sector. Consumers demand healthier meat products that are low in salt, fat, cholesterol, nitrites and calories in general and contain in addition health-promoting bioactive components such as for example carotenoids, unsaturated fatty acids, sterols, and fibers. On the other hand, consumers expect these novel meat products with altered formulations to taste, look and smell the same way as their traditionally formulated and processed counterparts. At the same time, competition is forcing the meat processing industry to use the increasingly expensive raw material "meat" more efficiently and produce products at lower costs. With these changes in mind, this article presents a review of novel ingredient systems and processing approaches that are emerging to create high quality, affordable meat products not only in batch mode but also in large-scale continuous processes. Fat replacers, fat profile modification and cholesterol reduction techniques, new texture modifiers and alternative antioxidant and antimicrobial systems are being discussed. Modern processing equipment to establish continuously operating product manufacturing lines and that allow new meat product structures to be created and novel ingredients to be effectively utilized including vacuum fillers, grinders and fine dispersers, and slicers is reviewed in the context of structure creation in meat products. Finally, trends in future developments of ingredient and processing systems for meat products are highlighted.

Combined Chitosan-Thyme Treatments with Modified Atmosphere Packaging on a Ready-to-Cook Poultry Product

In the present study, natural antimicrobials chitosan and thyme, and their combination, were evaluated for their effect on the shelf life of a ready-to-cook (RTC) chicken-pepper kebab (skewer) stored under modified atmosphere packaging (MAP) conditions at 4 ± 0.5°C for 14 days. The following treatments were examined: control samples stored under aerobic packaging (A), samples stored under MAP (M), samples treated with 1.5% chitosan (vol/wt) and stored under MAP (M-CH), samples treated with 0.2% thyme essential oil (vol/wt) (M-T), and samples treated with 1.5% chitosan (vol/wt) and 0.2% thyme essential oil (vol/wt) and stored under MAP (M-CH-T). Treatment M-CH-T significantly affected aerobic plate counts and counts of lactic acid bacteria, Pseudomonas spp., Brochothrix thermosphacta, Enterobacteriaceae, and yeasts and molds during the entire storage period. Similarly, lipid oxidation of the RTC product was retarded (M-CH-T treatment) during storage, whereas redness was maintained in M-T, M-CH, and M-CH-T samples. Based primarily on sensory data (taste attribute), M-CH and M-T treatments extended RTC product shelf life by 6 days, whereas M-CH-T treatment resulted in a product with a shelf life of 14 days that maintained acceptable sensory characteristics (shelf life of the control was 6 days).