Physicochemical Quality Changes Research Articles

Effects of high-energy electron rays on groundnut cake: Kinetics of aflatoxins degradation and changes in physicochemical quality

As a non-thermal technology, high-energy electron rays can effectively reduce pathogenic bacteria and mycotoxins in food. This study investigated the degradation effect of high-energy electron rays on four aflatoxins in artificially contaminated cold-pressed and hot-pressed groundnut cake. We also evaluated the irradiated groundnut cake's quality (including crude protein, amino acid, etc.). The results showed that the irradiation dose, and moisture content positively affected the degradation of aflatoxins, while the initial content of aflatoxins was detrimental to the degradation. The degradation process of aflatoxins could be better characterized by the second-order kinetics (R2 ranges 0.7162–0.9918) than first-order kinetics. The changes in the crude protein of groundnut cake by high-energy electron rays were small (all less than 3%). Still, there were some changes in the amino acid content of groundnut cake (less than 5% change in total amino acids in cold-pressed groundnut cake and no more than 8% change in total amino acids in hot-pressed groundnut cake). It was suggested that at the moisture content of about 11% and aflatoxins of about 160 μg/kg, 10–20 kGy could be used to ensure product quality and effective decontamination. In practice, the irradiation dose can be appropriately reduced when the moisture is high and increased when the initial contamination content is high. In conclusion, the high-energy electron rays are a practical option for industry to effectively degrade aflatoxins in defatted groundnut cake due to their cost-effectiveness, having little impact on product's nutritional value, and quick and easy to use without new environmental pollution.

Potency of Dimethyl Dicarbonate on the Microbial Inhibition Growth Kinetics, and Quality of Passion Fruit (Passiflora edulis) Juice during Refrigerated Storage.

This study aimed to investigate the effectiveness of dimethyl dicarbonate (DMDC) at various concentrations (0-250 ppm) in inhibiting the growth of Escherichia coli TISTR 117 and spoilage microbes in passion fruit juice (PFJ) and its impact on the physicochemical and antioxidant quality of the juice during refrigerated storage. The highest log reduction in the total viable count, yeast/molds and E. coli was attained in PFJ samples with 250 ppm of DMDC (p ≤ 0.05) added. Microbial growth inhibition by DMDC followed the first-order kinetic model with a coefficient of determination (R2) and inhibition constants (k) ranging from 0.98 to 0.99 and 0.022 to 0.042, respectively. DMDC at 0-250 ppm showed an insignificant effect on pH, °Brix, color (L*, a*, b*), ascorbic acid, total phenolic compound (TPC), total flavonoid content, and antioxidant activity (DPPH, FRAP) (p > 0.05). Control (untreated PFJ), DMDC-250 ppm, and pasteurized (15 s at 72 °C) samples were subjected to 27 days of cold storage at 4 °C. A decreasing trend in pH, total soluble solid, ascorbic acid content, DPPH and FRAP values were observed in all the samples during refrigerated storage. However, the DMDC-250 ppm sample showed a better prospect in physicochemical quality changes compared to the pasteurized and untreated control PFJ samples. ΔE values showed marked changes in the control sample than the DMDC-250 ppm and pasteurized samples at 27 days of storage. Additionally, the total viable count and yeast/mold count were augmented during storage, and an estimated shelf-life of the control, DMDC-250 ppm, and pasteurized samples was approximately 3, 24 and 18 days, respectively. In conclusion, DMDC at 250 ppm could ensure microbial safety without affecting the quality attributes of PFJ during 24 days of storage at 4 °C.

Microbial Growth and Physicochemical Quality Changes During Modified Atmosphere Storage of High Hydrostatic Pressure Processed Tenebrio molitor Paste

Microbial Growth and Physicochemical Quality Changes During Modified Atmosphere Storage of High Hydrostatic Pressure Processed Tenebrio molitor Paste

Synergistic effects of sequential treatment using disinfectant and e-beam for inactivation of hepatitis a virus on fresh vegetables

Hepatitis A virus (HAV) has adversely affected public health worldwide, causing an economic burden on many countries. Fresh vegetables are reported as a source of HAV infections during production, harvesting, and distribution, which cause the emergence of foodborne illnesses. Therefore, in this study, the synergistic effects of chemical (sodium hypochlorite [NaOCl] and chlorine dioxide [ClO2]) and physical (electron-beam [e-beam] irradiation) sequential treatment for HAV inactivation on fresh vegetables were investigated, and the physicochemical quality changes of vegetables were evaluated after each treatment. On bell pepper and cucumber sequentially treated with NaOCl (50–500 ppm) and e-beam (1–5 kGy), the HAV titer was reduced by 0.19–4.69 and 0.28–4.78 log10 TCID50/mL, respectively. Sequential treatment with ClO2 (10–250 ppm) and e-beam (1–5 kGy) reduced the HAV titer on bell pepper and cucumber by 0.41–4.78 and 0.26–4.80 log10 TCID50/mL, respectively. The sequential treatments steadily decreased the HAV titers on each food by a significant difference (p < 0.05) compared to the controls. The treatment combinations of 500 ppm NaOCl and 3 kGy (e-beam) on bell pepper and 150 ppm NaOCl and 1 kGy (e-beam) on cucumber provided maximum synergistic effects. It was also found that sequential treatment with 50 ppm ClO2 and 5 kGy (e-beam) on bell pepper and 10 ppm ClO2 and 5 kGy (e-beam) on cucumber most efficiently inactivated HAV. Additionally, bell pepper and cucumber showed no significant quality changes (p < 0.05) after the treatment. Therefore, the sequential treatment with NaOCl or ClO2 and e-beam is expected to effectively control HAV on fresh vegetables without changing the food quality compared to either treatment alone.

P06-013-23 Comparison of Physicochemical Quality Changes of Brown Cultivar Hypsizygus marmoreus According to Storage Period After Harvest

P06-013-23 Comparison of Physicochemical Quality Changes of Brown Cultivar Hypsizygus marmoreus According to Storage Period After Harvest

Changes in physicochemical quality and protein properties of porcine longissimus lumborum during dry ageing

SummaryThe present study investigated the effects of dry‐ageing time on physicochemical quality and protein properties of porcine longissimus lumborum within 48 h of postmortem ageing. Results showed that appropriately prolonged dry‐ageing time (24 and 36 h) had a positive effect on the tenderness, water‐holding capacity, thermal stability and gel properties of meat, as evident from the decrease of shear force, dripping loss, cooking loss, T2 relaxation time, enthalpy value and the increase in storage and loss modulus. Nevertheless, the excessive extension of ageing (48 h) increased the degree of protein oxidation and degradation by maintaining the lowest total sulfhydryl but the highest carbonyl content, and producing more small molecular weight protein chains (35.4, 20 and 19.6 KDa). Chemometric analysis further clarified the appropriate ageing time of desirable meat. In conclusion, dry ageing 24 and 36 h were suggested as the reasonable postmortem ageing time for porcine longissimus lumborum in China.

Effect of micro‐perforated film packing on physicochemical quality and volatile profile of button mushroom ( Agaricus bisporus ) during postharvest shelf‐life

The perishable characteristics of button mushrooms (Agaricus bisporus) decrease the physicochemical and change the flavor profile, affecting consumer purchase. In this study, button mushrooms were separately stored in the package with 0, 2, 4, 8, and 16 perforations for 8 days at 10°C, and whether the micro-perforated film packing delayed button mushrooms the changes in physicochemical quality and volatile profile was investigated. The results showed that 0 perforation packages could maintain the weight and firmness of button mushrooms. Micro-perforated film packing was found effective to decrease the browning index of button mushrooms during shelf-life. In addition, mushrooms in micro-perforation film packing had a lower concentration of 3 off-flavor compounds (2-methylbutanal, 3-methylbutanal, and ethanol) and a higher concentration of 13 mushroom characteristic flavor compounds than that in 0 perforation film when stored for 8 days. The 8 perforations groups had the most varieties of aroma impact compounds (odor active values, OAV ≥ 1), which contributed to the flavor profile of button mushrooms. It is concluded that film with 8 perforations could create an atmosphere condition to maintain the physiology quality and volatile profile of button mushrooms during shelf-life. Novelty impact statement The firmness of the mushroom was maintained due to the ethanol and low oxygen. 2-Methylbutanal, 3-methylbutanal, and ethanol were the main off-flavor compounds.

Improving the Storage Quality of Eggplants (Solanum Aethiopicum L.) Fruit using Aloe Vera Gel Coating

Aloe vera gel has been investigated as possible edible coating to help improve the storage life of fruits after harvest. The study sought to investigate the effect Aloe vera gel coating with or without citric acid pretreatment on the quality of eggplant fruits during low temperature storage and in shelf life. Briefly, eggplants were coated with Aloe vera gel (some fruits were pretreated with citrate prior to the coating) and the changes in physicochemical quality of the fruit measured during storage at 10 °C. After 14 days, however, some fruits were transferred for storage at room temperature until day 18. Coating with Aloe vera decreased moisture loss, and consequently, decreased weight loss and loss of firmness of the fruit. The coating did help maintain the phenolic content, ascorbate levels and antioxidant capacity of the fruit. Pre-treating the fruit with citrate did not improve quality, showing that Aloe vera gel can be applied alone to enhance the storage quality of eggplant fruit. Results obtained from this study shows that Aloe vera gel coating can be useful in extending the postharvest storage life and maintaining the quality of eggplant fruits during low temperature storage.

Organic Chilli Pepper (Capsicum annuum cv. Superhot) Quality and Biochemical Responses to Sequential Treatment with Hot Water, Surface Coating, Equilibrium Modified Atmosphere Packaging and Cold Storage

Organic chilli peppers (Capsicum annuum cv. Superhot) at full-red stage were submeged in 50°C water for 4 minutes followed by surface coating with carboxymethyl cellulose (CMC) or chitosan at 0.25-1.0% for 2 minutes. The fruits were then packed in 32-34 µm thick polyethylene bag (Active PAKTM) before cold storage at 10°C for 12 days followed by 5 days holding at 25°C. The decrease of fruit quality was due to weight loss and decay and these could be reduced by edible coating. Coated fruit had higher titratable acidity, vitamin C content, total phenols, and activities of phenylalanine ammonia lyase, superoxide dismutase and catalase as compared to uncoated fruit. Chitosan was more effective than CMC in bringing these effects, and 0.5% was the most effective concentration. The results indicated that fruit coating by 0.5% chitosan and CMC maintained quality of chilli peppers by slowing physicochemical quality changes and improving the antioxidant system.

Influence of electron beam treatment on naturally contaminated red pepper (Capsicum annuum L.) powder: Kinetics of microbial inactivation and physicochemical quality changes

This study reported the impact of electron beam (e-beam) treatment on microbiota and mycotoxins naturally present in red pepper powder and physicochemical quality changes. Treatment at 6 kGy indicated significant (p < 0.05) decontamination of yeasts and molds by 3.0 and 4.4 log CFU/g, respectively. A reduction of 4.5 log CFU/g of total plate counts (TPC) was observed at 10 kGy for 23 s. Fungal inactivation followed first-order kinetics while TPC better fitted with Gompertz function (R2 = 0.9912). E-beam treatment was not efficient for the degradation of aflatoxins but indirectly controlled their production by inactivation of mycotoxigenic molds. Indeed, reduction of 25% ochratoxin A was recorded at 30 kGy retaining >85% of total phenols, carotenoids and antioxidants activity. Moreover, treatment impact on total color difference (ΔE*) indicated ‘slight differences’. Overall, e-beam treatments up to 10 kGy were efficient in decontaminating the natural microbiota without detrimental effects on the physicochemical qualities of red pepper powder.

Modelling approaches for predicting moisture transfer during baking of chhana podo (milk cake) incorporated with tikhur (Curcuma angustifolia) starch

Chhana podo, a popular dairy product of India, is prepared by baking the dough of chhana (heat-acid coagulated milk solids), semolina and sugar. Heat induced moisture loss during baking influences the chain of physico-chemical changes, which in turn determine the quality of the final product. Thus, in this work, modelling approaches for predicting moisture transfer during baking of chhana podo prepared by replacing semolina with tikhur (Curcuma angustifolia) starch were developed. Moisture loss, moisture ratio, specific volume, oven spring, volumetric expansion and other physico-chemical quality changes of the dough were determined during baking, and were used in the development of moisture transfer models. The effective moisture diffusivity of chhana podo increased from 8.10 × 10–9 to 37.05 × 10–9 m2/s as baking temperature increased from 110 to 150 °C. The artificial neural networks (ANN) model based on multilayer feed-forward (MLFF) algorithm and radial basis function (RBF) and adaptive neuro-fuzzy inference system (ANFIS) models based on Sugeno-type fuzzy inference system were developed to predict moisture ratio, and their predictive performance was compared with classical multiple linear regression and empirical models. Amongst the four prediction approaches, the MLFF neural network with baking temperature and time as input factors, and with 12 neurons in the hidden layer, produced the best performance in predicting moisture ratio with R2 as high as 0.9946 (99.46% accuracy) and RMSE of 0.0188 for the entire range of baking temperature studied. Sensitivity analysis showed that baking temperature was the most influential parameter (strength ratio was 0.89) deciding moisture transfer. MLFF neural network was observed to be a simple and efficient technique for predicting the complex moisture transfer phenomenon during baking, which could be used by the industry to optimize the baking conditions.

Physicochemical Quality Changes in Tomatoes during Delayed Cooling and Storage in a Controlled Chamber

The exposure of tomato fruits to unfavorable environments during the postharvest could result in severe losses along the supply chain. In this research, four tomato cultivars were stored in a controlled chamber under three levels of postharvest conditions to investigate the effects of delayed cooling on selected physicochemical quality parameters of the tomatoes. The tomato cultivars were subjected to three postharvest treatments: Immediate storage (IS) at harvest day; delayed storage (DS), leaving tomatoes without cover for one day; and under cover (DSC), separately in a greenhouse, and then stored in a controlled chamber at a temperature of 10 ± 1 °C and relative humidity of 90% ± 3%. Fresh weight, firmness, total soluble solids (TSS), and hue angle (h°) were examined over 15 days, every 5 days. Among the tomato cultivars, Cherry (7160), treated under DS showed the highest weight loss (13.01%) and firmness loss (42.14%) after 15 days of storage. Dabol (large) tomatoes treated with DS showed higher changes in TSS (°Bx) values (4.79 to 5.76). Low changes in hue angle values were found in IS-treated Cherry (7160) tomatoes at the end of the storage period. Overall quality changes were slower for all tomato cultivars treated with IS than with other treatments throughout the storage period. This study indicated the importance of reducing cooling delays to maintain the quality during the postharvest and prolong storage of harvested tomatoes.

Influence of packaging materials, oxygen and storage temperature on quality of germinated parboiled rice

In this study, the effects of storage conditions of germinated parboiled rice (GPR) including packaging materials, oxygen, and temperature on its physicochemical qualities, bioactive compounds, antioxidant activity, sensory quality, and microbiological properties were investigated. GPR from purple rice (Oryza sativa var. ‘Hom Nil’) was packaged under vacuum and normal atmosphere in polyamide-polyethylene (PAPE) and aluminum-laminated polyethylene (ALPE) pouches and stored at 4 °C and 30 °C for 6 months. The results showed that storage at lower temperatures under vacuum in ALPE was effective in retarding the degradation of bioactive compounds, changes in physicochemical quality, and rancidity. Moisture content and water activity continuously declined during the storage in PAPE pouches at 30 °C while they were unchanged when stored in ALPE at 30 °C and under all conditions at 4 °C. At 30 °C, the gamma-aminobutyric acid and anthocyanins contents decreased as the storage time increased, however the contents in samples at 4 °C did not vary with time. Total phenolic content and antioxidant activities were also effectively retained under low temperature storage, especially in vacuum packaging. Rancidity of GPR determined using the thiobarbituric acid test, increased with storage time and showed a high correlation with sensory evaluation results (R2 = 0.9724). Storage at 4 °C also significantly conserved the color of GPR. In addition, bacterial count, yeast and mold count and aflatoxins content of the GPR did not exceed Thai standards under all tested conditions.

Inactivation mechanism of Salmonella Typhimurium on the surface of lettuce and physicochemical quality assessment of samples treated by micro-plasma discharged water

Abstract The potential of micro-plasma discharged water (m-PDW) treatment on reduction of Salmonella Typhimurium ATCC 14028 from the surface of lettuce leaves was evaluated. The surface of iceberg lettuce and red leaf lettuce pieces (3 cm × 3 cm) was inoculated with a S. Typhimurium suspension. The measured S. Typhimurium reductions were 3.0-log CFU/piece and 2.6-log CFU/piece for iceberg lettuce and red leaf lettuce, respectively for a 3-min treatment. The overall reductions measured for the levels of kaempferol and quercetin in both types of lettuce were within the experimental error for a 3-min plasma treatment. There was no significant change in color (p > 0.05) for plasma operations of the same duration. Leaching of water contributed to a greater extent towards physiochemical changes such as color constraints, kaempferol and quercetin content occurred for the treated lettuce samples, although the overall physicochemical quality changes measured in this study remains in the satisfactory level.

Physico-chemical Quality Changes of Young Cladodes of "Mexican Elephant Ear" Minimally Processed during Refrigerated Storage

Physico-chemical Quality Changes of Young Cladodes of "Mexican Elephant Ear" Minimally Processed during Refrigerated Storage

Degradation of paper mill wastewater sludge and cow dung by brown-rot fungi Oligoporus placenta and earthworm (Eisenia fetida) during vermicomposting

To evaluate the effect of brown-rot fungi Oligoporus placenta and earthworm Eisenia fetida on decomposition of paper mill sludge, the paper mill sludge was mixed with cow dung in 0, 25, 50, 75, and 100% proportions and changes in physicochemical quality of waste mixtures was carried out for 28 days. All waste mixtures were treated with: Setup-I (E. fetida), Setup-II (O. placenta) and, Setup-III (E. fetida + O. placenta). A decrease in total organic carbon, C/N ratio and cellulose but an increase in total kjeldhal nitrogen, total phosphorus, total potassium and pH was recorded. The paper mill sludge in 50–75% proportion in feedstock showed the better results and rate of mineralisation were in order: Setup-III > Setup-I > Setup-II. The proportion of CD has direct role in waste mineralisation. The microbial population (bacterial, fungal and actinomycetes) and earthworm biomass were also high in Setup-III, suggesting the influence of brown-rot fungi on paper mill sludge humification. Results indicate that fungal inoculate in vermicomposting was effective in decomposing cellulose-rich industrial sludge.

Changes in physico-chemical, astringency, volatile compounds and antioxidant activity of fresh and concentrated cashew apple juice fermented with Lactobacillus plantarum.

Changes in physico-chemical qualities (pH, total acidity, total and reducing sugar, total phenolic and vitamin C), astringency compounds (condensed and hydrolysable tannin), antioxidant activities [2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical] and flavor volatile compounds in Lactobacillus plantarum-fermented cashew-apple-juice (CAJ) and 11.4°Bx concentrated-cashew-apple-juice (CCAJ) was investigated. Total phenolics remained unchanged throughout fermentation period, whereas condensed tannins increased and hydrolysable tannins decreased indicating reduced astringency compounds. Antioxidant activity based on both DPPH and ABTS radical scavenging activities marginally declined in some stages but overall were sustained during fermentation. Although the DPPH· radical based antioxidant activity of fermented CAJ was greater than that of fermented 11.4°Bx CCAJ, a higher ABTS·+ radical scavenging activity was found in fermented 11.4°Bx CCAJ, reflecting higher water soluble antioxidants. Results also indicated that DPPH· radical scavenging activity was positively correlated to vitamin-C and condensed tannins but not hydrolysable tannins. ABTS·+ radical scavenging activity was also positively correlated to condensed tannins and not hydrolysable tannins. The vitamin-C that increased during initial 12h fermentation, decreased from 2516 to 2150mg AAE/L at the end of 72h fermentation. Fermented CAJ had a remarkable sweet aroma with a fruity note of two major compounds; 3-methyl-1-butanol (14.20 × 107) and 2,6-dimethyl-4-heptanol (14.76 × 107). The high phytochemicals and volatile compounds in fermented CAJ indicated that it could serve as a functional beverage with potential health benefits with reduced astringency due to lower hydrolysable tannins.

Evaluation of gamma irradiation effect on physico-chemical properties of a mixed beverage based in soy milk and grape juice

The aim of this study was to evaluate the effect of gamma radiation on the physico-chemical parameters in a mixed beverage (white or red grape juice + soy milk). The radiation doses were used: 1, 3, 6 and 9 kGy. Most of the parameters evaluated did not change in both beverages at different doses, with the exception of the 9 kGy dose that reduced the antioxidant capacity and the phenolic compounds, and increased the peroxidase. Thus, the gamma radiation can be used in mixed beverages, but doses below 9 kGy, avoiding changes in physico-chemical quality.

Microbial, enzymatic and physico-chemical quality changes during storage of tomatoes (Solanum lycopersicum) harvested from polyhouse vs. open conditions

Protected cultivation of vegetables is gaining importance owing to its perpetual demand throughout the year. Effect of cultivating tomato (Solanum lycopersicum L.) cultivar Himsona under polyhouse conditions on the microbial and physico-chemical quality and enzymatic behavuior was studied and compared with open conditions at the time of harvesting and during storage under ambient conditions. Study on microflora of tomato fruits grown under open and polyhouse conditions revealed presence of fungi, viz. Acremonium sp., Rhizopus sp. and Aspergillus sp. in fruits harvested from open while fruits under polyhouse condition contained fungus Acremonium sp. only. Spoilage started in open fruits from 6th day of storage under ambient conditions due to dominance of Rhizopus sp. The bacterial counts on polyhouse grown fruits were about 100 times less than open cultivated fruits. Polygalacturonase activity was initially higher (0.139 U/ml) in open conditions compared to polyhouse condition (0.074 U/ml). It increased sharply to 1.50 U/ml on 4th day of storage in open conditions compared to slow increase under polyhouse condition (0.140 U/ml). On 6th day senescence started as evidenced by decrease in polygalacturaonase activity and increase in surface fungal counts in fruits from open conditions, which finally spoiled on 8th day due to dominance of Rhizopus sp. The fruits from polyhouse were still marketable at the end of 8th day. The study proves that tomato fruits grown in polyhouse are microbiologically safer and have better shelf life.

Tree age and fruit size in relation to postharvest respiration and quality changes in ‘Kinnow’ mandarin fruit under ambient storage

The conducted research focused on the impact of tree age and fruit size on postharvest respiration as well as changes in physico-chemical quality of ‘Kinnow' mandarin fruit, stored in ambient conditions (20±2°C). Fruit from three different tree age groups (6, 18 and 35-years) and fruit size (large, medium and small) groups were analyzed for respiration and fruit quality during seven days ambient storage. Fruit from tree age group of 35-years surpassed the fruits from tree age group of 6-years in carbon dioxide (CO2) production, while fruit size had non significant influenced CO2 production following ambient storage. Ethylene production was predominantly more in fruit from tree age group of 35-years, while fruit of small size irrespective of tree age group had significantly higher ethylene production. In general, CO2 production indicated a non-climacteric pattern, while ethylene production followed climacteric pattern, with two peaks. As regards fruit quality, fruit of tree age group of 35-years, had more TSS (10.6°Brix) titratable acidity (TA) (0.81%), sugars {reducing (1.9%), non reducing (5.3%) and total sugars (7.5%)} as compared to tree age group of 6 and 18-years. Final fruit quality data after seven days of ambient storage showed more decrease in TA (0.1%) and reducing sugars (0.26%) and increase in ascorbic acid (AA) (3.38mg 100mL−1) and non reducing sugars (0.61%) in fruit of trees age group of 35-years. Fruit from 18-years old trees had higher mass loss (8.39%), irrespective of fruit size and the interactive response of tree age and fruit size revealed that more mass loss (11.71%) was observed in small sized fruit from 18-year-old trees. Ethylene production was positively correlated with mass loss (r=+0.734) in fruit from 18-year-old trees and negatively (r=−0.692) in fruit from 6-year-old trees. Irrespective of tree age and fruit size ethylene and CO2 correlated positively with TSS, titratable acidity and total sugars and negatively with rind thickness.