Presented work evaluated how quality of catfish fillets is affected by treatments using lactic acid or lysozyme in combination with chlorine. Fish fillets without skin were consecutively immersed and washed in 100 ppm chlorine solution and sprayed with 2.5% lactic acid or 0.5% lysozyme solution. Control samples were only washed with water at the same time. Samples were stored at 2 °C for 10 days in vacuum packaging. Parameters of pH, firmness, surface color and microbial cell counts (cfu/g) were measured on the 1st, 4th, 7th and 10th days. Especially the latter had high importance from the point of view of food safety. Catfish fillets shown decreased survival of microorganisms as a result of treatment. Lysozyme and lactic acid achieved 1.8 and 2.4 log cfu/g reduction, respectively. Lower cell counts were observed for all treated samples compared to control during 10 days. Chlorine in combination with lactic acid achieved the best efficiency. The results are promising and suggest that combined treatment is able to improve safety by controlling microorganisms on fish fillets during cold storage.
The effect of storage temperature and ozone treatment on the post-harvest quality of cucumber and tomato was investigated. Cucumber and tomato were stored together with or without gaseous ozone treatment at 20 °C and 14 °C for 16 days. Firmness, color, weight loss, DA index and decay percentage of samples were evaluated during storage period. The results showed that the combination of ozone treatment and cold storage could maintain the quality of these horticultural products and decreased the decay incidence. Additionally, this combination also reduced the weight loss of samples during storage. Furthermore, ozone treatment maintained the green skin color of cucumber. No sign of chilling injury occurred during storage at 14 °C. Commodities stored with approximately 0.1 ppm gaseous ozone at 14 °C retained the firmness compared to other treatments until the end of the experiment. This study suggests a promising use of gaseous ozone treatment in storage chamber where ethylene-producing and ethylene-sensitive vegetables are stored together.
Broccoli's high perishability and its sensitivity to negative quality changes (i.e., mass loss, ethylene induced degreening, abscission of leaves, and florets) generates quality problems during postharvest. Freshly harvested samples were stored at 5 and 21 °C after separately treated for 24 h with 625 ppb 1-methyl-cyclopropene (1-MCP), 24 h with 2 ppm ethylene and 1-MCP followed by ethylene. Quality maintenance effectivity of 1-MCP was investigated during cold and room storage by non-destructive optical methods (chlorophyll fluorescence and DA-index®) and by the evaluation of the visual physiological symptoms. The highly positive effects of 1-MCP treatment combined with cold storage were obviously proven on quality maintenance providing better retention of initial quality related to the initial mature green stage as chlorophyll content related DA-index®; Fm, Fv, Fv/Fm, and Fm/F0 chlorophyll fluorescence values. From the practical point of view, the rapid, and easy-to-use Sintéleia FRM01-F Vis/NIR DA-meter® could be applied relatively easy for the quality measurement of broccoli. The reproducibility of quality determination could be increased by the enhanced number of measuring points or using computer aided imaging methods (i.e., chlorophyll fluorescence imaging, machine vision system) providing global and more reliable information about quality changes.
The aim of this work was to evaluate the effect of packaging perforation on quality of carrot slices during cold storage at 5 °C. Polyethylene bags with different number of perforations (3, 4, and 6) were used in this experiment. Headspace oxygen concentration, respiration, weight loss, surface color, firmness, pH, and soluble solid content were examined throughout storage. It was observed, that all the investigated packaging were effective in maintaining the quality of carrot slices compared to the control. There was no symptom of decay until 12 days. In addition, pH, soluble solid content, and firmness showed nonsignificant change. Moreover, weight loss of packed carrot slices was below 2% after 12 days of storage. Packed carrot had better appearance at the end of experiment (12 days) than that of control.
In this work, the simulated adulteration of coconut drink by dilution with water was investigated using laser-light backscattering (LLB) imaging. The laser vision system consisted of six low power laser modules, emitting 1 mm diameter beams at wavelengths of 532, 635, 780, 808, 850 and 1,064 nm. The backscattering images were acquired by a grey scale camera with 12 bit resolution. Eight parameters were extracted to describe the backscattering profile. The methods of linear discriminant analysis (LDA) and partial least squares (PLS) regression were performed on LLB parameters for classifying and predicting dilution level of adulterated coconut drink samples. Based on the results, LLB signals responded sensitively to adulteration. LDA results showed that adulterated samples were correctly recognized with accuracies between 60 and 100%. PLS models were able to estimate the adulteration level of samples with coefficients of determination of 0.57–0.97 in validation. This result demonstrated the potential of laser-light backscattering imaging as a rapid and non-destructive optical technique for evaluation of coconut drink adulteration.
This study focuses on the contribution of maturity stages and 1-methylcyclopropene (1-MCP) treatment to the quality of ‘Zebra’ apricot. Samples were harvested at mature-green, yellow and orange maturity stages. Fruit were treated with gaseous 1-MCP (24 h at 1 °C), followed by cold storage at 1 °C for 6 weeks. Non-destructive measurements were used to evaluate the quality changes of apricot during storage. The results showed that the maturity stages significantly affected the weight loss. The loss of weight increased rapidly for orange ripeness stage fruit, more than others during storage. Both maturity and 1-MCP affected the stiffness of apricot. The 1-MCP could delay the softening of fruit. The green and yellow maturity stages retained higher values in stiffness compared to orange. No significant difference in hue angle values was observed between 1-MCP treated and control fruit, however hue angle value decreased strongly in mature-green harvested fruit. The maturity stages and 1-MCP treatment had the effect on quality changes of apricot over storage. The maturity stage was an important factor contributing to the effectiveness of 1-MCP application as it was observed in slower softening after harvest.
This work was aimed to investigate the effect of 1-methylcyclopropene (1-MCP), ethylene absorber (EA), ozone alone or in combination on melon quality during storage. Ethylene production, respiration rates, acoustic firmness, surface color, chilling injury, and disease severity of melon were determined. 1-MCP treated fruits and non 1-MCP treated fruits were stored with sachets of ethylene absorber containing KMnO4 or ozone at 0.1 ppm/h during 10 days at 5 °C and subsequent 4 days at 20 °C. Melons treated with 1-MCP were firmer than the rest of the samples during storage. In addition, 1-MCP reduced the yellowing of melon rind compared to other treatments. The combination of 1-MCP and EA did not offer any additional effect in comparison with 1-MCP alone. There was no significant difference between fruits stored with ethylene absorber, ozone and control samples. Ozone treatment during cold storage decreased disease severity, however, fruits exposed to ozone had more serious decay throughout storage at 20 °C, probably due to the unclean air in the chamber.
Banana is a really chilling injury sensitive product. Its sensitivity to cold temperatures generates serious practical, economical and commercial problems. Chilling injury related physiological responses of Cavendish type green banana samples stored at 2.5, 5, 10 °C and near optimal (15 °C) cold storage temperature were investigated by nondestructive optical methods (surface color and chlorophyll fluorescence measurement, DA-index® evaluation) and by the determination of the physiological reactions (respiration, ethylene production, symptom manifestation) during cold storage and the 8-day long subsequent shelf-life. The positive effects of low temperature storage were proven on mass loss, respiration and ethylene production. In case of bananas stored at 2.5–10 °C, the chilling injury related changes in chlorophyll content related DA-index®, IR-values; Fm and Fv chlorophyll fluorescence values, the L*, a*, b*, C* and hue angle color characteristics suggested clearly from day 3 the onset of chilling injury several days before the visible signs of chilling injury appeared.
The presented study investigated the effects of edible coatings with concentration of 2%, 3% and 4% of starch (w/v) on the weight loss and firmness loss of green asparagus during 4 days of storage at room temperature (26 ± 2 °C, 65–70% RH). According to the results, the coated asparagus exhibited significantly slower deterioration rate than the uncoated control samples. This was indicated by the decrease in weight loss and increase in firmness (P < 0.05). After the storage period, the samples treated with 4% starch formula retained the highest quality. Furthermore, the assessment of asparagus quality throughout the storage period involved the use of the line laser scattering technique. Extracted parameters of laser scattering signal discriminated samples with linear discriminant analysis (LDA), in which the correct recognition rate of the treated groups was 75.26% and the storage time was 70.54%. This study showed the potential of laser scattering as a rapid, non-invasive, and practical optical method for assessing the quality of asparagus during storage.
The aim of this study was to evaluate the effect of edible coating on hydroponic strawberry during storage. Strawberries were coated with either 1% or 1.5% chitosan (CS) or with solution containing 1.5% chitosan and 0.5% calcium gluconate (CaGlu). After treatment, samples were stored at 10 °C, RH 90% for 10 days. The weight loss, soluble solid content, firmness, surface color, pH, and percentage of decay were evaluated each day during the experiment. It was observed that coating extended the postharvest life of hydroponic strawberry compared to control. Fungal growth occurred on control group at the 5th day and fruit treated with 1% CS at the 8th day of the storage period, whereas no visible sign was detected for other treatments. Soluble solid content and pH showed only minor change for all samples. Weight loss of coated fruit was below 6% after 10 days of storage, whereas the weight loss of control samples was around 10% at the end of measurement. Moreover, coating could maintain the firmness of strawberry compared to the control. The combination of chitosan and calcium gluconate showed the potential for prolonging the storage period of hydroponic strawberry till 10 days without decay, whereas the control sample had more than 60% of rotted fruit.