Combined effect of steaming and gamma irradiation on the quality of mango pulp stored at refrigerated temperature

The effect of steaming mango fruits (12 min) followed by γ-irradiation treatment (0.0–2.0 kGy) of the extracted pulp on the chemical, microbiological, rheological and organoleptic quality of mango pulp stored at 3±1°C was studied. The obtained results indicated that steaming mango fruits before irradiation (1.0–2.0 kGy) of the pulp increased the shelf life of refrigerated pulp to 270 days compared with 90 days of unsteamed irradiated ones and 15 days for control (unsteamed and unirradiated). The combined treatment improved the hygienic and microbiological quality of the pulp without undesirable effects on their chemical, rheological and sensory properties. In addition, yeast species belonging to six genera namely Candida, Hanseniaspora, Rhodoterula, Saccharomyces, Saccharomycodes and Zygosaccharomyces were isolated from unsteamed and unirradiated mango pulp. The D₁₀ values of the isolated yeasts were higher in mango pulp than in saline solution for each strain.     

Shelf Life and Microbial Quality of Fresh-cut Mango Cubes Stored in High CO2 Atmospheres

ABSTRACT: Fresh-cut'Carabao'and'Nam Dokmai'mango cubes were stored in air or in high CO₂ atmospheres (3%, 5%, and 10%) at 5 °C and 13 °C. Freshly sliced'Carabao'mango cubes had a lower respiration rate and total bacterial count and higher L-ascorbic acid content and firmness than'Nam Dokmai'mango cubes. The shelf life of fresh-cut mango, based on browning discoloration and water-soaked appearance, was 6 d at 5 °C and 4 d at 13 °C for'Carabao'and 2 d at 5 °C and less than 1 d at 13 °C for'Nam Dokmai'. High CO₂ atmospheres retarded the development of water-soaked'Carabao'cubes at 5 °C and 13 °C and'Nam Dokmai'cubes at 5 °C. Texture of'Carabao'cubes was enhanced by high CO₂, but ethanol and L-ascorbic acid contents were not affected at 5 °C and 13 °C. Total bacterial count was lower in'Carabao'cubes than in'Nam Dokmai'cubes during storage at both temperatures, and a 10% CO₂ only reduced the bacterial count on'Carabao'and'Nam Dokmai'cubes stored at 13 °C. Bacterial flora in'Nam Dokmai'mango cubes consisted mostly of Gram-negative rods assigned primarily to phytopathogenic bacteria such as Pantoea agglomerans and Burkholderia cepacia . The genera of bacteria isolated from cubes stored in 10% CO₂ were similar to those from cubes on the initial day.     

Reduction of chilling injury in ripe Alphonso mango fruit in cold storage by temperature conditioning

The influence of ripening temperature and cold conditioning of pre-climacteric fruits on the incidence of chilling injury (CI) in ripe mango fruits cv. Alphonso during refrigerated storage was investigated. Fruits previously held and ripened at tropical ambient temperature (AT, 27–34°C) developed CI (skin staining or browning) when ripe fruits were subsequently stored at 5, 10, or 15°C for shelf-life extension. Fruits held and ripened at 20°C1°C, RH 85–90% showed little evidence of CI when subsequently stored at 5 or 10°C up to 14 days. Chilling injury in ripe mangoes was also avoided by holding pre-climacteric fruits for a minimum period of 30 days at 10°C and then ripening them at 27–34°C. The quality of the ripe mangoes remained good during cold storage for 7 days and were acceptable until 10–14 days with minimal changes in texture, flesh colour, carotenoids, total soluble solids, titratable acids and ascorbic acid. Shelf-life of ripe mangoes can thus be extended under refrigeration by pre-storage conditioning.     

Preservation and shelf-life extension of shrimps and clams by high hydrostatic pressure

Clam ( Venus gallina ) and shrimp ( Parapenaeus longirostris ) samples were high hydrostatic pressure (HHP) treated at 200, 220 and 250 MPa at 25, 30, 40 and 50 °C for 10 and 20 min. Based on the results of microbial reduction, the best combinations of HHP treatments were determined as 250 MPa, 50 °C, 10 min for shrimps and 220 MPa, 50 °C, 10 min for clams. HHP-treated samples stored at 25 °C (room tempertur) and 4 °C (refrigeration temperature) were analysed. According to the results evaluated, shelf-life of shrimps was found to be 12 and 16 days for storage at room and refrigeration temperatures, respectively, as compared with 4 days for non-HHP-treated samples at 4 °C. Similarly shelf-life for the clam samples was found to be 12 days for storage at room temperature and 18 days for storage at refrigeration temperature as compared with 4 days for non-HHP-treated samples at 4 °C.     

ACCELERATED STORAGE, SHELF LIFE AND COLOR OF MANGO POWDER

Vacuum‐dried mango powder was produced from mango pulp through the addition of glycerol monostearate and tricalcium phosphate at 0.015 kg each per kg mango solids and maltodextrin at 0.62 kg per kg dry mango solids. The mango powder was packed in aluminum foil‐laminated pouches and stored in an accelerated storage environment maintained at 90% relative humidity (RH) and 38 ± 2C. The sticky‐point moisture content at 38 ± 2C was considered as the maximum moisture content to which the mango powder would remain stable. The shelf life of the powder predicted from this consideration and the Guggenheim‐Anderson‐de Boer (GAB) model for the water activity moisture content relationship was 114.68 days, whereas the actual shelf life was 105 days. The color change of the powder during storage followed first‐order reaction kinetics with a rate constant of 0.038 per day.     

A "Cold Shortening" Effect in Avian Muscle

SUMMARY— Experiments were conducted to determine the effect of post-mortem temperatures between 0 and 20°C on the degree of shortening in isolated pectoralis major muscles of chickens and turkeys. A "cold shortening" effect in these muscles is described and compared to post-mortem pH, average sarcomere length of isolated myofibrils, and relative solubility of myofibrillar and sarcoplasmic proteins.
The degree of muscle shortening at each temperature after various periods post-mortem indicated that shortening was essentially complete after 3 hr in chickens and 5 hr in turkeys. Shortening in muscles stored at 0°C was significantly greater (P < .01) than in the 12–18°C temperature range. Shortening was greatest in muscles stored at 20°C. The degree of gross shortening observed was directly related to the average sarcomere length of isolated myofibrils. Post-mortem decline in pH was not significantly correlated (P > .05) with shortening. Extractability of myofibrillar and sarcoplasmic proteins after 5 hr at either 0 or 16°C was determined and found to be unrelated to the degree of post-mortem shortening.     

Improving antioxidant capacity of fresh-cut mangoes treated with UV-C

ABSTRACT:  The effect of UV-C irradiation time on total phenol, flavonoids, β-carotene, ascorbic acid contents, and antioxidant capacity (ORAC, DPPH^•) of fresh-cut "Tommy Atkins" mango stored for 15 d at 5 °C was investigated. Fresh-cut mango was irradiated for 0, 1, 3, 5, and 10 min prior to storage at 5 °C. UV-C irradiation for 10 min induced a hypersensitive defense response resulting in the phenols and flavonoids accumulation which was positively correlated with ORAC and DPPH^• values. However, β-carotene and ascorbic acid content of fresh-cut mangos decreased with irradiation time during storage. Antioxidant capacity (ORAC, DPPH^•) was increased in fresh-cut mangoes treated with UV-C irradiation. In conclusion, UV-C irradiation appears to be a good technique to improve the total antioxidant capacity of fresh-cut mango.     

DRY ICE IN VARIOUS SHIPPING BOXES FOR CHILLED POULTRY: EFFECT ON MICROBIOLOGICAL AND ORGANOLEPTIC QUALITY

SUMMARY– Comparisons were made of dry ice and weter ice in shipping boxes for chilled chickens. Three types of boxes were tested: wax-resin-coated corrugated fiberboard, expanded polystyrene foam, and wirebound wood-veneer. Microbial counts, CO₂ concentration, and off-odor development were determined. Microbial counts on poultry stored at 0.5°C for up to 9 days were not significantly different as a function of box type or coolant. Counts on poultry stored at 4.4°C were significantly greater at 9 days on poultry stored in fiberboard boxes with dry ice than on poultry with water ice in fiberboard boxes or polystyrene boxes with dry ice; at 3 and 6 days there were no significant differences. At 5.2°C, counts were significantly smaller in polystyrene boxes with dry ice than in either wirebound boxes with water ice or fiberboard boxes with dry ice. An off-odor not characteristic of spoilage odor could develop in CO₂ atmosphere storage earlier than spoilage odor in an air atmosphere if storage temperature was low (0.5°C). At higher temperature (5.2°C), spoilage odor in air occurred earlier than Co₂-related off-odor in Co₂ atmosphere.     

The yeast flora of stored ready-to-use carrots and their role in spoilage

Spoilage of ready-to-use grated raw carrots packaged in polymeric films and stored at 10°C was investigated for involvement of yeasts. Cryptococcus albidus was only isolated during the first 3 days of storage, increasing to levels of 10⁵–10⁶g^-1. Candida lambica was more commonly isolated after 3–7 days of storage, and reached 10⁷–10⁸g^-1 after 12 days. Candida sake was present throughout storage, increasing from 10⁵–10⁶ after 3 days to 10⁷–10⁸ after 12 days. In some samples, Candida parapsilosis and Candida tropicalis were also isolated at levels similars to C. sake . All the yeasts isolated at the end of storage were fermentative species and their metabolism was characterized with a Warburg apparatus. Neither the number of yeasts nor the composition of the yeast flora were related to the deterioration of the product. Although Candida lambica inoculated on grated carrots caused spoilage after 12 days at 10°C, the high O₂ permeable film was most effective in reducing exudate.     

EFFECT OF PECTIN CONTENT ON FLOW PROPERTIES OF MANGO PULP CONCENTRATES

The effect of pectin on the flow properties of mango pulp concentrates was studied using a coaxial cylindrical viscometer in the temperature (T) range 303-343°K. The variables were soluble solid content(C) 16-30°Brix, pectin content (C_pec, range 0.0323-0.0349 dry wt fraction) for the shear rate (γ) range 9.0-250 s^-1. Mango pulp concentrates behaved as pseudoplastic fluids in the entire pectin content range with a flow behaviour index of 0.286. A model relating shear stress () with the above variables is presented:     

Susceptibility of minimally processed green pepper and cucumber to chilling injury as observed by apparent respiration rate

Apparent respiration rate and total microbial count were measured for intact and cut vegetables of green chilli pepper and cucumber stored at 5 and 10 °C. The minimally processed vegetables were more sensitive to chilling injury at 5 °C compared to the intact produce. Their response of increased respiration to chilling injury at 5 °C was noticed earlier than spoilage due to microbial growth, and determined the limit of shelf-life (4 days) in storage. Due to increased susceptibility to chilling injury when these products were stored at 5 °C, they had shelf-lives shorter than or equal to those at 10 °C.     

GAMMA IRRADIATION, HOT WATER AND IMAZALIL TREATMENTS ON DECAY ORGANISMS AND PHYSICAL QUALITY OF STORED NETTED MUSKMELON FRUIT

Nonchemical treatments of gamma irradiation (2 Kilograys) and hot water (57°C) and the fungicide imazalil (1000 ppm) were compared with and without shrink-film wrap for effects on decay and physical quality of netted muskmelon fruit stored at 4°C for 0 through 60 days. Gamma irradiation was ineffective in controlling decay and surface molds, and injurious to physical quality by decreasing firmness, increasing fresh weight loss, membrane leakage and vein track browning. Hot water treatment coupled with shrink-film wrap was effective in controlling decay activity and maintaining physical quality up to 20 days storage. Imazalil coupled with shrink-film wrap controlled the incidence and severity of decay and maintained fruit firmness, moisture loss, membrane permeability and vein track browning for almost 60 days storage.     

VACUUM PACKAGING OF LAMB. 1. Microbial Considerations

SUMMARY –Paired loins from 148 lamb carcasses were utilized to determine the subsequent case-life of chops from loins that had been stored in vacuum packages. Bacterial samples which were obtained from the surface of the longissimus muscle were used to evaluate the retail case-life of loin chops. Longer periods of storage in vacuum packages were associated with higher initial psychrotrophic counts for subsequent loin chops. Comparisons between vacuum packaged loins that were stored at 0°C vs. 7°C indicated that storage temperatures of 7°C were more favorable for psychrotrophic bacteria growth and thus resulted in decreased subsequent case-life for chops from these loins. 8 days appears to be a reasonable maximum period for the storage of loins in vacuum packages. Fresh chops that were fabricated 8 days postmortem and displayed immediately exhibited an advantage of 1½1/4 days of increased case-life in comparison to those chops from loins which were vacuum packaged 8 days postmortem, stored under vacuum for 8 days, fabricated and subsequently displayed. The average case-life of fresh chops was 3½1/2 days when stored in a retail case at 0°C. The results of the present study indicate that vacuum packaging of lamb loins may be feasible; however, unless low storage temperatures are maintained and the storage interval is short, the retail case-life of chops will be reduced.     

Effect of packaging and frozen storage temperature on beef pigments

The influence of final freezing and storage temperature on pigment modifications of beef samples wrapped in polyethylene and EVA/SARAN/EVA was analysed. Met-, oxy- and myoglobin relative surface concentrations were determined using reflectance spectrophotometry. Pigment behaviour during storage of beef packaged in both films and oxygenation of vacuum-packaged samples was described by different reaction schemes and modelled to obtain kinetic and equilibrium constants. Comparative studies performed with beef samples (a) refrigerated, (b) frozen to –5°C and stored at this temperature (partial freezing), and (c) frozen to -25°C and stored at -5 and -20°C, indicated that for aerobic storage periods of 90 days, metmyoglobin levels of partially frozen samples upon thawing were comparable to those of frozen samples stored at –20°C. For vacuum-packaged beef, pigment concentrations remained practically constant during frozen storage; partial freezing increased oxygenation capacity of the tissue compared with chilled and frozen conditions.     

Patterns of Peroxidase in Ripening Mango (Mangifera indica, L.) Fruits

Chemical and biochemical changes in Lippens and Smith mango cultivars stored at 12°C and 85–90% RH were studied. The observed chemical changes were similar in both varieties. Peroxidase (POD) activity increased in pulp tissues up to the climacteric stage of ripening. In a parallel way, the quantity of extractable proteins decreased from preclimacteric to ripe or senescent fruits. Polyacrylamide gel electrophoresis of the extracts from Smith mangoes revealed three isoenzymes of POD which moved towards the anode at pH 8.3. The isoenzyme pattern of POD of Lippens mango extracts was quite different, showing four faster moving bands in addition to the above mentioned three characteristic bands of Smith mango fruits. Relative activity of the different isoenzymes changed during ripening may provide insight into the ripening process.     

Tropical fruit pulps decreased probiotic survival to in vitro gastrointestinal stress in synbiotic soy yoghurt with okara during storage

The effect of mango and guava pulps on Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 viability in a soy yoghurt (SY) and on probiotic survival under simulated gastrointestinal conditions were investigated throughout 28 days of storage at 4 °C. The impact of fruit pulps on SY sensory acceptability was also assessed. Three formulations were produced from soymilk fermented with ABT-4 culture (La-5, Bb-12, and Streptococcus thermophilus) and supplemented with inulin and okara: SYC (control), SYM (with mango pulp), and SYG (with guava pulp). All formulations showed probiotic viabilities ranging from 8 to 9 log cfu/g, and fruit pulps did not affect the probiotic viabilities. However, the fruit pulps decreased probiotic survival significantly to simulated gastrointestinal stress. Acceptability was higher for SYM and this difference was significant at 21 days. Therefore, the improved acceptability of SY through the addition of fruit pulps might lead to a reduction in probiotic functionality.     

Influence of whole and fresh-cut mango intake on plasma lipids and antioxidant capacity of healthy adults

The content of antioxidant compounds and antioxidant capacity of whole and fresh-cut mango, stored for 10 days at 12 °C and 5 °C, respectively and their influence on serum antioxidant capacity and lipid profile of normolipidemic humans were studied. Whole mango (WM) had a higher content of flavonoids, ??-carotene and antioxidant capacity, determined by oxygen radical scavenging capacity, (ORAC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, than the fresh-cut fruit (FCM). FCM presented higher amounts of total phenols. Thirty normolipidemic volunteers, ages 20-50 years, were randomly divided into two groups (WM and FCM) 15 persons each. During 30 consecutive days volunteers from groups 1 and 2, received daily 200 g of WM or FCM, respectively. Lipid levels and antioxidant capacity in plasma were determined at 0, 15 and 30 days of the experiment. Serum triglycerides were significantly reduced after 30 days of supplementation with WM and FCM (37 and 38% respectively); VLDL levels were reduced in a similar proportion. No significant changes in other plasma lipid levels were observed. Both treatments increased plasma antioxidant capacity measured by ORAC and TEAC methods. According to the results obtained in this study, we suggest that addition of mango fruit to generally accepted healthy diets could have a beneficial effect preventing hypertryglyceridemia, and that fresh-cut processing does not affect the beneficial properties of mango.     

Effect of Osmotic Dehydration and Vacuum-Frying Parameters to Produce High-Quality Mango Chips

ABSTRACT:  Mango ( Mangifera indica  L.) is a fruit rich in flavor and nutritional values, which is an excellent candidate for producing chips. The objective of this study was to develop high-quality mango chips using vacuum frying. Mango (" Tommy Atkins ") slices were pretreated with different maltodextrin concentrations (40, 50, and 65, w/v), osmotic dehydration times (45, 60, and 70 min), and solution temperatures (22 and 40 °C). Pretreated slices were vacuum fried at 120, 130, and 138 °C and product quality attributes (oil content, texture, color, carotenoid content) determined. The effect of frying temperatures at optimum osmotic dehydration times (65 [w/v] at 40 °C) was assessed. All samples were acceptable (scores > 5) to consumer panelists. The best mango chips were those pretreated with 65 (w/v) concentration for 60 min and vacuum fried at 120 °C. Mango chips under atmospheric frying had less carotenoid retention (32%) than those under vacuum frying (up to 65%). These results may help further optimize vacuum-frying processing of high-quality fruit-based snacks.     

PHYSICO-CHEMICAL CHANGES DURING ENZYMATIC LIQUEFACTION of MANGO PULP (cv. Keitt)

Mango pulp from Keitt variety was liquefied with 1.1 mL/kg commercial enzyme mixture preparations for 2 h at 40C. Various physico-chemical characteristics of the mango pulp at different stages of liquefaction were investigated. Apparent viscosity of pulp and serum reduced rapidly to 78% and 93% respectively, in 30 min liquefaction. No marked changes in apparent viscosity of pulp samples and percentage cell wall hydrolysis in the subsequent 60, 90 and 120 min were observed. High correlation coefficient values (R² > 0.99) of the linear regression analysis showed the feasibility of using a power law model for fitting the shear stress-shear rate data of the pulp. the enzymetreated pulp showed 83% and 84% serum yields during 30 and 120 min reaction times respectively against 52% for fresh pulp. Slight increase in TSS (°Brix), acidity, reducing and total sugars, and slight decrease in pH was found in the pulp as well as serum fractions as the incubation continued. No marked change in color (yellowness) was observed in the enzyme-treated pulp, however, the corresponding serum showed less yellowness and color saturation indicating retention of yellow pigments in the pulp fraction. Δ-3-carene was identified as major mono terpenic compound in mango pulp comprising more than 73% of the total aroma compounds. About 9% loss in the total aroma components was observed during the liquefaction process.     

Inactivation of Saccharomyces cerevisiae and polyphenoloxidase in mango nectar treated with UV light

Fresh mango nectar was processed by UV light at five flow rates (0.073 to 0.451 liter/min) and five UV light doses (75 to 450 kJ/m2) to evaluate total microbial load, Saccharomyces cerevisiae survival, and polyphenoloxidase activity. UV systems containing an inner mercury lamp (254 nm) each with intensity of 25 mW/cm2 were used as germicidal sources. In addition, mango nectar was treated for 15 min at 0.073 and 0.451 liter/min, stored at 3 degrees C, and evaluated periodically for total microbial count, yeast count, color, and polyphenoloxidase activity. The first-order kinetics modeling found that DUV-values in mango nectar ranged from 27.9 to 10.9 min (R2 > 0.950) and 26.0 to 11.8 min (R2 > 0.962) for total microbial count and yeast count, respectively. The maximum log reduction (CFU per milliliter) was 2.71 and 2.94 for total microbial count and yeast count, respectively, after 30 min of UV treatment at 0.451 liter/min. DUV-values ranging from 156 to 204 min were observed for polyphenoloxidase activity. The remaining polyphenoloxidase activity after 30 min of UV treatment at 0.451 liter/min was 19 +/- 4%. Initial microbial load and yeast in stored mango nectar were reduced in the range 2.86 to 3.41 and 1.82 to 1.97 log (CFU/ml) cycles, respectively. No substantial microbial growth was observed prior to 20 days of storage. Averages of 1,055 +/- 32, 803 +/- 32, and 710 +/- 37 enzyme activity units were observed in mango nectar UV processed at 0, 0.073, and 0.451 liter/min, respectively, during the entire storage period. However, mango nectar treated at 0.073 and 0.451 liter/min maintained a yellow and yellow-orange color, respectively, after 26 days of storage.