BackgroundMicrobial activity is a primary cause of deterioration in many foods and is often responsible for reduced quality and safety. Food-borne illnesses associated with E. coli O157:H7, S. aureus, S. enteritidis and L. monocytogenes are a major public health concern throughout the world. A number of methods have been employed to control or prevent the growth of these microorganisms in food. Antimicrobial packaging is one of the most promising active packaging systems for effectively retarding the growth of food spoilage and pathogenic microorganisms. The aim of this study was to determine the mechanical, physico-chemical properties and inhibitory effects of the fish gelatin films against selected food spoilage microorganisms when incorporated with catechin-lysozyme.ResultsThe effect of the catechin-lysozyme combination addition (CLC: 0, 0.125, 0.25, and 0.5%, w/v) on fish gelatin film properties was monitored. At the level of 0.5% addition, the CLC showed the greatest elongation at break (EAB) at 143.17% with 0.039 mm thickness, and the lowest water vapor permeability (WVP) at 6.5 x 10−8 g·mm·h-1·cm-2·Pa-1, whereas the control showed high tensile strength (TS) and the highest WVP. Regarding color attributes, the gelatin film without CLC addition gave the highest lightness (L* 91.95) but lowest in redness (a*-1.29) and yellowness (b* 2.25) values. The light transmission of the film did not significantly decrease and nor did film transparency (p>0.05) with increased CLC. Incorporating CLC could not affect the film microstructure. The solubility of the gelatin based film incorporated with CLC was not affected, especially at a high level of addition (p>0.05). Inhibitory activity of the fish gelatin film against E.coli, S.aureus, L. innocua and S. cerevisiae was concentration dependent.ConclusionsThese findings suggested that CLC incorporation can improve mechanical, physico-chemical, and antimicrobial properties of the resulting films, thus allowing the films to become more applicable in active food packaging.
Preharvest bagging with different wavelength-selective materials affected mango development and quality. Bagging mangoes with VM and V materials could reduce peel defects and diseases, increase weight, size, and sphericity, improve peel appearance, and shorten the development periods of mangoes. The results suggest a favorable practice using the newly developed VM and V plastic bags in the production of mangoes, and possibly other fruits as well.
Antimicrobial activities of six potential active compounds (acetic acid, chitosan, catechin, gallic acid, lysozyme, and nisin) at the concentration of 500 g/ml against the growth of Escherichia coli, Staphylococcus aureus, Listeria innocua, and Saccharomyces cerevisiae were determined. Lysozyme showed the highest antimicrobial activity against L. innocua and S. cerevisiae with an inhibition zone of 19.75 and 17.37 mm, respectively. Catechin was strongly active against E. coli, L. innocua, and S. aureus with 15.37, 19.38, and 17.00 mm of inhibition zone diameter, respectively. The minimum inhibitory concentration (MIC) value of catechin for E. coli and for S. aureus was the same at 640 g/ml, while the minimum bactericidal concentration (MBC) values were 640 and 1,280 g/ml, respectively. The MIC and MBC values of lysozyme for L. innocua were 160 and 640 g/ml, respectively. S. cerevisiae was the most susceptible microorganism to lysozyme among others, since both its MIC and MBC were the lowest (2.5 g/ml). However, catechin and lysozyme were combined in equal amounts; all tested microorganisms were effectively inhibited as indicated by both qualitative and quantitative antimicrobial activities. This study thus revealed the potential application of some active compounds such as catechin and lysozyme for their usage in food products.
This paper presents the effects of different packaging systems and fruit orientation on bruising and pre-cooling time of pineapples during distribution. The package types studied were reusable plastic containers, single-use paper corrugated containers and plastic foam containers (FCs). Simulated vibration tests were performed to evaluate the shipping containers on their protective performances. After the vibration tests, pineapples were evaluated for bruise damage and decay during storage for 5 days. Pineapple fleshes were also evaluated for bruise volume and changes in colour, firmness, total soluble solids content (TSS) and titratable acidity (TA) after storage of 5 days. Bruise damage was more intense as the storage time increased. Package types had significant effects (p ≤ 0.05) on bruise damage of pineapples. The corrugated containers showed the best protective performance for pineapples, while the FCs showed the worst. The corrugated containers with paperboard partitions showed the lowest damage levels as compared to other package types studied. Foam-net cushion reduced bruise damage of pineapples. L values and firmness of pineapple flesh were highly associated with degree of bruising. The results suggested that slight bruising on the skin may signify severe bruising on the flesh and bruising accelerated decay in pineapples. Orientation did not show a significant effect (p ≤ 0.05) on bruising. The highest pre-cooling rates were observed in the reusable plastic containers, while the slowest rates were observed in the single-use paper containers. The results indicated that careful handling in the proper packaging with optimum cushion can minimize bruise damage and decay of pineapples after shipments.
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