Effect of chitosan edible coating enriched with lemon verbena extract and essential oil on the shelf life of vacuum rainbow trout (Oncorhynchus mykiss)

In this research, the antioxidant and antibacterial characteristics of the chitosan (CH) coating incorporated with lemon verbena essential oil (LVEO) and extract (LVE) on the quality of the rainbow trout packed by vacuum packaging at 4°C were investigated. Samples evaluated include the following: Control, VP, CH, CH-LVE 2%, CH-LVEO 1%, and CH-LVE 1%-LVEO 0.5% for 16 days at 3 days intervals. All of the samples significantly reduced Psychrotrophic bacteria, total viable counts, Enterobacteriaceae, and H₂S producing bacteria as compared with control during keeping time. Thiobarbituric acid reactive substance, peroxide value, total volatile basic nitrogen, and pH value were detected lower in all of the samples than control. CH incorporated with LVE and LVEO gave an agreeable effect on sensory characteristics. Samples containing CH-LVE 1%-LVEO 0.5% was often in priority by sensory assessors. Generally, LV can be applied as a substitution for chemical preservatives in fish meat.     

Increased shelf life of Oncorhynchus mykiss (Rainbow trout) through Cu-Clay nanocomposites

Food Science and Biotechnology - Microbial growth is widely responsible for shortened shelf life of cold water-living fish products. So, it seems that current chemical-based food packaging has no...     

Combined effects of a natural Allium spp. extract and modified atmospheres packaging on shelf life extension of olive‐based paste

This study aimed to extend the shelf life of non‐thermally stabilised olive‐based paste by adding different concentrations (0.2, 0.5, 1.0 g kg^?1) of a natural Allium spp. extract and/or by using different packaging atmospheres (MAP1, 75% Ar‐23% CO₂‐2% H₂; MAP2, 70% N₂‐30% CO₂) during refrigerated storage. Higher amounts of the natural extract gave the highest level of microbial inhibition, increased hardness, a greater release of aldehydes, esters, and ketones, and a better colour preservation when used with MAP1. The natural extract and MAP, either alone or in combination, produced no sensory defects (except for the control in MAP2), but a greater loss of typical olive flavour. The addition of the natural extract used with an appropriate MAP, can retain the quality attributes and extend shelf life for approximately 14 days longer than the control (without natural extract and MAP), and a better performance is achieved by using greater amounts of natural extract and MAP1.     

Novel approaches for chemical and microbiological shelf life extension of cereal crops

Abstract

Economic losses due to post-harvest fungal spoilage and mycotoxin contamination of cereal crops is a frequently encountered issue. Typically, chemical preservatives are used to reduce the initial microbial load and the environmental conditions during storage are controlled to prevent microbial growth. However, in recent years the consumers’ desire for more naturally produced foods containing less chemical preservatives has grown increasingly stronger. This article reviews the latest advances in terms of novel approaches for chemical decontamination, namely application cold atmospheric pressure plasma and electrolyzed water, and their suitability for preservation of stored cereal crops. In addition, the alternative use of bio-preservatives, such as starter cultures or purified antimicrobial compounds, to prevent the growth of spoilage organisms or remove in-field accumulated mycotoxins is evaluated. All treatments assessed here show potential for inhibition of microbial spoilage. However, each method encounters draw-backs, making industrial application difficult. Even under optimized processing conditions, it is unlikely that one single treatment can reduce the natural microbial load sufficiently. It is evident that future research needs to examine the combined application of several treatments to exploit their synergistic properties. This would enable sufficient reduction in the microbial load and ensure microbiological safety of cereal crops during long-term storage.     

Effect of salep‐based edible coating enriched with grape seed extract on postharvest shelf life of fresh strawberries

Effects of novel edible coatings based on salep solution (SS) enriched with grape seed extract (GSE) (1.5% SS, 1.5% SS + 0.5% GSE, 1.5% SS + 1.5% GSE, 1.5% SS + 3% GSE) on the quality characteristics of fresh strawberries were monitored after 0, 4, 8, 12, 16, and 20 days of storage (1°C, 95% RH). The lowest growth of microorganisms, weight loss, softening and ascorbic acid, phenol and anthocyanin degradation was measured in strawberries coated with 1.5% SS + 3% GSE. The highest superoxide dismutase activity and the lowest peroxidase activity were determined in strawberries coated with 1.5% SS + 3% GSE. Moreover, they received the highest ranked sensory attributes. Incorporating GSE into the SS coating formulation as a new hurdle increased its antimicrobial properties and extended the shelf life of coated strawberries compared to uncoated by up to 20 days.     

Improved quality and shelf life of farmed trout (Oncorhynchus mykiss) by whole processing in a combined ozonised flow ice refrigeration system

A combined refrigeration system consisting of ozone and flow ice was evaluated for the sacrifice, cooling and chilled storage of continental trout. The batch processed in ozonised flow ice exhibited significant ( P  < 0.05) reductions (0.97 and 1.51 log CFU cm⁻²) in skin aerobes and psychrotrophs on days 6 and 9, respectively, and significant ( P  < 0.05) reductions (0.94 log CFU g⁻¹ and 0.96 log CFU g⁻¹) in aerobes, and proteolytic bacteria in muscle on day 13. A significant ( P  < 0.05) inhibition of TMA-N formation after 9 days was also observed, with an average reduction of 28.4% along the storage period, Slight reductions in autolytic breakdown mechanisms were also observed in the ozonised batch, a maximum reduction of 14.82% being reached on day 13. The microbial and biochemical changes were well correlated with the sensory evaluation, which revealed relevant differences between the batches on day 13 and a shelf life extension of the ozonised batch up to day 16.     

Spoilage and shelf‐life extension of fresh fish and shellfish

Fresh fish and shellfish are highly perishable products due to their biological composition. Under normal refrigerated storage conditions, the shelf life of these products is limited by enzymatic and microbiological spoilage. However, with increasing consumer demands for fresh products with extended shelf life and increasing energy costs associated with freezing and frozen storage, the fish‐processing industry is actively seeking alternative methods of shelf life preservation and marketability of fresh, refrigerated fish and at the same time economizing on energy costs. Additional methods that could fulfill these objectives include chemical decontamination, low‐dose irradiation, ultra‐high pressure, and modified atmosphere packaging (MAP). This review focuses on the biochemical and microbiological composition of fresh fish/shellfish, the spoilage patterns in these products, factors influencing spoilage, and the combination treatments that can be used in conjunction with refrigeration to extend the shelf life and keeping quality of fresh fish/shellfish. The safety concerns of minimally processed/MAP fish, specifically with respect to the growth of Clostridium botulinum type E, is also addressed.     

百里香精油抗菌涂层包装对鲜切生菜货架期内理化品质及微生物的影响

精油抗菌涂层包装是一种环保的包装技术。文中利用百里香精油抗菌涂层包装膜包装鲜切生菜,通过检测鲜切生菜货架期内的呼吸强度、抗坏血酸含量、多酚氧化酶活性、菌落总数等指标,并结合生菜感官品质,对比普通PE食品保鲜膜与抗菌包装膜在不同贮藏温度下(1、4、10℃)的保鲜效果差异,最后通过荧光假单胞菌的回接实验探究薄膜对鲜切生菜的优势腐败菌的抑制效果。结果表明:精油抗菌包装膜能较好地抑制鲜切生菜的呼吸强度、微生物生长及多酚氧化酶的活性,减少贮藏期内VC的损失,维持生菜良好的感官品质。当与4℃的低温贮藏结合时,可将鲜切生菜的货架期延长至5 d。     

Gelatin nanocomposite films incorporated with magnetic iron oxide nanoparticles for shelf life extension of grapes

Nanocomposite films were obtained by solution casting method from aqueous solution of bovine gelatin with addition of various concentrations of magnetic iron oxide (MIO) nanoparticles (NPs) (5, 10, 15, and 20% w/w of dry gelatin). The incorporation of MIO NPs improved the mechanical and physical properties of the nanocomposites. The increase in concentration of NPs up to 10% improved barrier and mechanical properties which slightly decreased after increasing the concentration beyond that limit due to particle agglomeration. The scanning electron microscopy and X-ray diffraction (XRD) were used to evaluate the morphology and crystalline structure of gelatin nanocomposite films, respectively. Gelatin nanocomposites with 20% w/w NPs exhibited the highest antimicrobial activity against Escherichia coli (7.1 ± 0.085 mm) and Staphylococcus aureus (8.22 ± 1.04 mm). Finally, the potential of gelatin/MIO nanocomposites as packaging material was evaluated to extend the shelf life of grapes. The gelatin/MIO nanocomposites can be used as a replacement to non-biodegradable packaging.     

Applications of chitosan for improvement of quality and shelf life of foods: a review

ABSTRACT:  Chitosan is a modified, natural biopolymer derived by deacetylation of chitin, a major component of the shells of crustacean. Recently, chitosan has received increased attention for its commercial applications in the biomedical, food, and chemical industries. Use of chitosan in food industry is readily seen due to its several distinctive biological activities and functional properties. The antimicrobial activity and film-forming property of chitosan make it a potential source of food preservative or coating material of natural origin. This review focuses on the applications of chitosan for improvement of quality and shelf life of various foods from agriculture, poultry, and seafood origin.     

Effectiveness of gelatine and chitosan spray coating for extending shelf life of vacuum-packaged beef

The effects of applying gelatine (10%) and chitosan (1%) as spray coatings to extend the shelf life of vacuum-packaged beef was studied and compared against uncoated vacuum-packaged beef for up to 21 days. The impact of edible coatings on the water-holding properties of vacuum-packaged beef was investigated by LF-NMR together with physicochemical, microbiological and sensorial assessments. Chitosan coating significantly reduced lipid oxidation by ~30% to 36% and inhibited the growth of lactic acid bacteriaby ~ 1–2 log cfu compared to purge collected from uncoated and gelatine coated samples. It did not negatively affect the meat pH, tenderness and colour, and exhibited significantly higher sensorial acceptance compared to beef coated with gelatine. Both coatings were not effective in reducing purge loss in vacuum-packaged meat as the storage time increased. This study suggests that chitosan spray coating could be easily adapted to industrial plant settings as an antioxidant and antimicrobial application before carrying out meat vacuum packaging operation.     

Plasticizer types and coating methods affect quality and shelf life of eggs coated with chitosan

ABSTRACT:  Effects of different plasticizer types (glycerol, propylene glycol, and sorbitol) and coating methods (brushing, dipping, and spraying) on the internal quality and shelf life of chitosan-coated eggs were evaluated during 5 wk of storage at 25 °C. The Haugh unit and yolk index values suggested that chitosan coating, irrespective of the plasticizer types, extended the shelf life of eggs by almost 3 wk at 25 °C compared with noncoated eggs. After 5 wk of storage, plasticizer types did not significantly affect the quality (weight loss, Haugh unit, and yolk index) of chitosan-coated eggs. However, there was an observable trend indicating that use of sorbitol rather than propylene glycol and glycerol as a plasticizer was better in reducing weight loss (whole egg) of chitosan-coated eggs during a 5-wk storage. After a 5-wk storage, there were no significant differences in weight loss and weight of albumen and yolk among chitosan-coated eggs, regardless of the coating methods. However, both brushing and dipping methods yielded chitosan-coated eggs with better yolk (higher yolk index values) and albumen (lower pH) qualities than did the spraying method. During 3 to 5 wk of storage, the Haugh unit values of chitosan-coated eggs by the brushing method were higher than or comparable to those by dipping or spraying. Therefore, coating of eggs with chitosan using sorbitol as a plasticizer and by the brushing method may offer a protective barrier in preserving the internal quality and thus extending shelf life of eggs.     

Coconut husk extract: antibacterial properties and its application for shelf-life extension of Asian sea bass slices

Antibacterial properties of ethanolic coconut husk extracts (ECHE) prepared using varying ethanol concentrations as the extracting media against Pseudomonas aeruginosa, Escherichia coli, Vibrio parahaemolyticus, Listeria monocytogenes and Staphylococcus aureus was studied. ECHE60, prepared using 60% ethanol, had similar minimum inhibitory concentration and minimum bactericidal concentration to those extracted using 80% and 100% ethanol (P ˂ 0.05). When Asian sea bass (Lates calcarifer) slices were treated with ECHE60 at 200 and 400 ppm, the quality changes were monitored in comparison with the control (without treatment) during 12 days of refrigerated storage (4 °C). The shelf life of sea bass treated with 400 ppm ECHE60 was extended to 9 days, whereas the control had a shelf life of 3 days. Lipid oxidation was lowered in ECHE60 treated samples than the control during storage. Therefore, ECHE60 could inhibit both spoilage and pathogenic bacteria and also extended the shelf life of sea bass slices.     

Antimicrobial and antioxidant effects of clove oil on sliced smoked Oncorhynchus mykiss

The antimicrobial and antioxidant effects of clove oil (Eugenia caryophyllata) on sliced smoked rainbow trout fillets were evaluated during storage at 2 °C. Smoked fillets were divided into four groups: a control (C0) without clove oil, a second group with 0.1 % (v/w) clove oil (C0.1), a third group with 0.5 % (v/w) clove oil (C0.5) and the fourth group with 1 % (v/w) clove oil (C1). Results showed that significantly higher values of TBA (thiobarbituric acid) and PV (peroxide value) as well as microbiological growth (p < 0.05) could be observed for the control group. In addition, the shelf life of smoked fish treated with clove oil (C0.5 and C1) has extended by 4–5 weeks compared to the control samples. As a result, clove oil can be utilized as natural preservative for smoked fish under chilled storage.