Storage Stability of Orange Juice Concentrate Packaged Aseptically

Orange juice concentrates were packaged aseptically by a “Dole” aseptic canning machine using 6 oz metal cans. The final juice products (11°, 34°, 44°, 58° Brix) were stored between ?18° and 36°C and tested periodically for nonenzymatic browning, ascorbic acid destruction, furfural and sensory changes. Nonenzymatic browning, the main deterioration phenomena in these products, was satisfactorily retarded at 12°C or lower. Ascorbic acid destruction rate constant was dependent on temperatures between 5 and 25°C, and was affected by degree of juice concentration. Furfural accumulation in juice was higher than that in 58° Brix concentrate. Orange juice concentrate of 58° Brix did not show flavor changes after storage at 5°C or 12°C for 17 or 10 months, respectively, when evaluated after reconstitution to 11° Brix.     

Time and Temperature Effect on Stability of Moroccan Processed Orange Juice during Storage

The loss of quality of processed pasteurized orange juice stored at 4°C, 22.5°C, 35°C, and 45°C for up to 14 wks was evaluated. The results showed that parameters such as pH, total solids, titratable acidity, formal index, and total sugars did not significantly change during storage at all temperatures. However, a major change was observed for ascorbic acid content, reducing sugars and furfural production, except for storage temperature at 4°C. Ascorbic acid degradation, sucrose hydrolysis, and furfural build-up followed pseudo-zero order reaction kinetics. The minimal change of formol number and total sugars suggested that nonenzymatic browning was mainly due to ascorbic acid degradation. Fufurfal formation during storage was found to be much higher than that reported in the literature.     

Protection of vessel permeability by genistein against lipopolysaccharide induced acute inflammation in a chick embryo chorioallantoic membrane model

Effects of dip treatments on nutritional quality preservation during the shelf life of fresh-cut tomato (Licopersicum esculentum Mill.) cv. Eufrates were investigated. Fresh-cut tomatoes were dipped in solutions of 2% ascorbic acid, citric acid, and calcium lactate for 2 min, then stored at 4°C for 20 days. Color (L*, a*, and b*), firmness, °Brix, phenolics, ascorbic acid content, antioxidant activity (DPPH), and sugars were measured during storage. Pathogen development was monitored, and a sensory evaluation was performed. Ascorbic acid was better in maintaining firmness. No treatments significantly affected °Brix, color, or sugars. Ascorbic acid maintained a higher antioxidant capacity, phenolics, and ascorbic acid content, and was better at reducing bacterial growth, while citric acid treatment was better at prevention of yeast and molds proliferation. Fresh-cut tomatoes showed good quality after 10 days of shelf life, except for flavor with the calcium lactate treatment. Ascorbic acid treatment better preserved the general and nutritional quality parameters.     

Ascorbic Acid Stability in Ground Asparagus Samples and in Oxalic Acid Extracts

To establish the storage conditions for asparagus preparation before ascorbic acid determination, samples were ground, the mass was divided into three aliquots that were, respectively, stored at 4°C, – 18°C, or extracted with 1% oxalic acid. The extract was further split into aliquots and stored at 25°, 4°, –18° and -75°C. Ascorbic acid content was measured at different times of storage by a polarographic method. The rate of degradation increased with storage temperature; the degradation rate was higher in ground samples than in extracts; no significant changes in ascorbic acid content were observed in extracts stored for 7 days at -18° or for 90 days at -75°C.     

Effects of gamma irradiation and storage temperature on carotenoids and ascorbic acid content of mangoes on ripening

Synthesis and accumulation of carotenoids in the flesh of Alphonso mangoes on ripening was found to be maximal in fruits stored at tropical ambient temperatures (28–32°C). Gamma irradiation of preclimacteric fruits at 25 krad did not affect the formation of carotenoids. Storage of preclimacteric fruits either irradiated or unirradiated at 7–20°C for 16–43 days caused a substantial reduction in carotenoid formation even when these fruits were subsequently ripened under optimal conditions. Regardless of storage temperature, carotenes always exceeded xanthophylls in the ripe fruits and, in general, irradiated fruits showed higher levels of carotenes in comparison with unirradiated samples. Ascorbic acid loss during ripening was maximum at ambient temperatures while lengthy storage at low temperatures caused a net increase in ascorbic acid levels. Irradiation seemed to accentuate the loss in ascorbic acid during ripening.     

Effects of ascorbic acid retention on juice color and pigment stability in blood orange (Citrus sinensis) juice during refrigerated storage

Blood orange juice samples with two different levels of ascorbic acid content were placed in HDPE plastic bottles, pasteurized, and stored at 4.5 °C. The influence of ascorbic acid retention on color stability of blood orange juice was investigated using CIE L*a*b*, hue, chroma, polymeric color, and browning index during the storage period. Changes in monomeric anthocyanin pigments, total carotenoid contents, cyanidin-3-glucoside, and ascorbic acid were also measured. Ascorbic acid degradation was highly correlated (r>0.93) to anthocyanin pigment degradation. Ascorbic acid content also showed linear correlation with red color intensity (CIE a*, and chroma) in the juice. Polymeric color and browning index increased with storage time and were more pronounced for juice fortified with ascorbic acid.     

Chemical Changes during Storage of an Alcoholic Orange Juice Beverage

Chemical stability of a pasteurized, noncarbonated, alcoholic orange juice beverage, (8% ethanol and 30% reconstituted Valencia frozen concentrated orange juice), was investigated. It was hot-filled into clear glass bottles under nitrogen and subjected to 14-wk storage at 4, 25, and 40°C. pH, °Brix, titratable acidity, and % alcohol remained constant throughout storage. Accumulation of furfural and darkening paralleled ascorbic acid degradation. The beverage exhibited 25 times more browning at 40°C and 9 times more at 25°C than at 4°C after 14-wk. d-Limonene decreased at all temperatures. Nitrogen headspace slightly improved stability at 40°C. Time and temperature were most significant in storage and long-tem shelf-life could only be achieved with refrigeration.     

Ascorbic Acid Retention in Orange Juice Stored under Simulated Consumer Home Conditions

Ascorbic acid levels in 13 types of commercially packaged orange juices and a juice drink were monitored over 5–7 days at 4.5°C as stored in the original container. Comparable samples stored in an open plastic container were monitored for comparison. In both cases the average ascorbic acid loss was about 1.5–2% per day. These simulated consumer home conditions showed that juice retained an average of 88% of the original ascorbic acid after 1 wk, and 67% after 2 wk in opened containers stored at typical home refrigerator temperatures.     

Shelf Life and Quality of Freshly Squeezed, Unpasteurized, Polyethylene-Bottled Citrus Juice

Florida's chief orange and grapefruit cultivars were used to produce five freshly squeezed, unpasteurized, polyethylene-bottled juices using commercial conditions. Juices were stored at different temperatures. Shelf life depended primarily on storage temperature: ?1.7°C, 20–23 days; 1.1°C, 16–22 days; 4.4°C, 10–16 days; and 7.8°C, 5–8 days. Staleness was the primary off-flavor limiting shelf life at the three lower temperatures while spoilage with diacetyl was primarily responsible at 7.8°C. At the three lower temperatures, microbial counts generally decreased markedly during storage, while at 7.8°C, an increase was generally noted. Ascorbic acid retention after 2 wk of storage at the three lowest storage temperatures was about 91–93% for two orange juices and 86–88% for the grapefruit juice.     

Effect of refrigerated storage on ascorbic acid content of orange juice treated by pulsed electric fields and thermal pasteurization

Application of pulsed electric fields (PEF) can lead to longer shelf life of fruit juices with minimal product quality loss and good retention of fresh-like flavour. The aim of this study was to evaluate the effect of PEF and conventional pasteurization (90 °C, 20 s) on ascorbic acid content of orange juice, and to assess modifications in ascorbic acid concentration of orange juice stored in refrigeration at 2 and 10 °C for 7 weeks. The ascorbic acid degradation rate was −0.0003, −0.0006, −0.0009 and −0.0010 μs⁻¹ for fields of 25, 30, 35 and 40 kV/cm, respectively. With selected PEF treatment (30 kV/cm and 100 μs) the shelf life based on 50% ascorbic acid losses was 277 days for the PEF-treated orange juice stored at 2 °C, while for the pasteurized juice was 90 days.     

Cutting Shape and Storage Temperature Affect Overall Quality of Fresh-cut Papaya cv. 'Maradol'

: The effect of cutting shape (cubes or slices) and storage temperature (5 °C, 10 °C, and 20 °C) on overall quality of fresh‐cut papaya were investigated. CO₂ production, color, firmness, total soluble solids (TSS), weight loss, overall quality, ascorbic acid, β‐carotene, and antioxidant capacity were evaluated as a function of shelf life. CO₂ production was high on day 0 for cubes and slices with an average of 150 and 100 mL/ kg/h, respectively. Storage temperature did not affect color changes; however, lower temperatures prevented loss of firmness. Fresh‐cut papaya stored at 20 °C showed the lowest TSS value and the highest weight losses. Shelf life based on visual quality ended before significant losses of total ascorbic acid, b‐carotene, and antioxidant capacity occurred. In general, quality parameters were not affected by shape. However, slices stored at 10 °C and 5 °C had a shelf life of 1 d and 2 d longer than cubes, respectively.     

Effect of Storage Temperature on the Stability of Aseptically Packaged Concentrated Orange Juice and Concentrated Orange Drink

Commercial orange drink concentrate and two orange juice concentrates were aseptically packed in flexible bags and stored at 4°, 15°, 22°, and 30°C for 6 months. Ascorbic acid, nonenzymatic browning and sensory quality were measured monthly. Sensory characteristics for drink concentrate deteriorated after 3 and 4 months at 30°C and 22°C, respectively. Juice concentrates were unacceptable after 2 and 5 months at 30°C and 22°C, respectively. Drink concentrate ascorbic acid loss was greater than juice concentrates at 4°, 15°, and 22°C. Changes in nonenzymatic browning as measured by Hunter color and by absorbance at 420 nm were similar to changes in other containers. The quality of refrigerated aseptic drink (15°C) and juice (4°C) was similar to frozen concentrates (?18°C).     

Quality of Enzymatically Treated 72° Brix Orange Juice Stored at Refrigerated Temperatures

Fresh Valencia orange juice was treated with 0, 70, and 350 ppm of commercial pectic enzymes, concentrated to 72° Brix and stored at –7°, –1°, 7°, and 13°C for up to 6 months. The 70 ppm enzyme treatment successfully reduced initial apparent viscosity by about 25%. For the 70 ppm enzyme treated samples after 6 months storage at all four temperatures, juice cloud remained acceptable, furfural remained below the significant level, and at ?1°C, vitamin C levels were above 32 mg/100 mL. There was no significant difference in taste after 6 months storage at ?7°C between control and 70 ppm enzyme treated samples. Product quality of enzymatically treated orange concentrate stored at refrigerated temperatures was of sufficient quality to realize potential savings of 17% in storage and 30% in refrigeration.     

The effect of storage on the antioxidant activity of reconstituted orange juice which had been pasteurized by high pressure or heat

The effect of storage on the antioxidant activity of pasteurized reconstituted orange juice was studied. Either heat or high pressure was used for pasteurization and total antioxidant activity and ascorbic acid loss were measured during storage at different temperatures (0, 5, 10, 15 °C). The total antioxidant activity of orange juice, calculated as the sum of the activities of different antioxidant compounds, decreased during storage. This was mainly because of loss of ascorbic acid. However, rates of degradation of ascorbic acid were lower for orange juice treated with high pressure and this led to a better retention of its antioxidant activity when compared with juice pasteurized in a conventional way.     

QUALITY CHANGES DURING STORAGE IN KOREAN CLEAR PEAR JUICES CONCENTRATED BY THREE METHODS

Pears of Shingo variety were coarsely ground, and subjected to heat treatment by HTST (high temperature short time) and pectinase treatment to produce a cloudy pear juice. The pear juice was then treated with Viscozyme, gelatin and bentonite, and filtered through an ultrafiltration membrane to produce a clear pear juice. The clear pear juice was concentrated to 3 to 5 fold by vacuum evaporation, freeze concentration, and reverse osmosis methods. The concentrates were diluted to 10° Brix and stored at 4C for 15 days. The single strength juice was evaluated for color, turbidity, heat stability, and sensory preference at 5 day intervals during storage. The pear juice concentrated by the three methods showed only small differences in quality. While the clear pear juice with added ascorbic acid had no quality changes at 4C after 15 days' storage, that without the addition of ascorbic acid resulted in some deterioration in browning, turbidity and heat stability after 10 days' storage. There were small, but significant flavor differences among clear pear juices concentrated by evaporation, freeze concentration and reverse osmosis.     

Factors Affecting Storage of Orange Concentrate

Orange concentrate (OC) 66°Brix, was tested for effect of storage temperature and storage time on product quality. OC was stored at −12.2, −6.6, −1.1, and 4.4°C, and analyzed for °Brix, % acid, ascorbic acid, furfural, serum viscosity, apparent viscosity, browning, Hunter color values, and taste panel scores at monthly intervals for 1 yr. Significant (p > 0.01) decreases were found in ascorbic acid content and Hunter color value (Y) due to storage time, and temperature. Nonenzymatic browning increased and taste panel scores significantly decreased with storage temperature and time. Taste panelists were able to detect significant differences in flavor after 5 and 9 months at 4.4 and −1.1°C, respectively.     

VITAMIN C AND β-CAROTENE IN FRESH AND FROZEN GREEN BEANS AND BROCCOLI IN A SIMULATED SYSTEM

The reduced ascorbic acid and β-carotene contents of “retail market-fresh” (RMF) and “fresh-frozen” (FF) green beans and broccoli in a simulated handling system were determined. Changes in ascorbic acid content in the two vegetables during a retail market period and frozen storage followed different patterns. In green beans, ascorbic acid content decreased during refrigerated storage for up to 7 days, but in broccoli there was a significant increase. Blanching resulted in a loss of approximately 40% of the ascorbic acid in broccoli. Ascorbic acid content of FF green beans stored at-20C for 16 weeks was approximately twice that in RMF green beans, but in FF broccoli stored under the same conditions it was only about half that of RMF broccoli. β-carotene content of green beans and broccoli did not change during either the retail market simulation of frozen storage and did not differ from that of fresh.     

Preparation and storage stability of juices from different carrot species

Carrot juice was prepared from each of yellow-, orange-, and purple-coloured carrots. Juice preparation included sorting, washing, peeling, acid-blanching, chopping, juicing, sterilization, and bottling steps. Bottled juices were stored in incubators which were kept at 5 °C, 20 °C, and 27 °C. Analytical determinations of pH, total soluble solids, maximum absorbance, reducing sugar, ascorbic acid, and β-carotene were made in suitable time intervals. Each of the three types of carrot juice kept at 27 °C deteriorated organoleptically in the first two weeks of storage. Juices stored at 20 °C and 5 °C were stable up to seven and twelve weeks, respectively. It was concluded that each of the carrot species can well be used for the preparation of carrot juice.     

Kinetic and prediction studies of ascorbic acid degradation in normal and concentrate local lemon juice during storage

Kinetics of the loss of ascorbic acid (AA) in local lemon juice of 9° and 50° Brix stored at 25, 35, and 45 °C for 4 months have been investigated. The results indicate that increases of concentrations and temperatures increase the rate of AA degradation. The calculated values of activation energies (E^≠) and frequency factors (A) at different Brix imply that the concentration of juice does not change the mechanism of degradation. Thermodynamic functions of activation (ΔG^≠, ΔH^≠, ΔS^≠ and K^≠) have been determined and considered briefly. A direct equation for estimation of the shelf life of stored juice with respect to first-order losses of AA, at any specific temperature and degradation ratio, has been derived and programmed successfully.     

Degradation Kinetics and Storage Stability of Vacuum Spray-Dried Micro Wet-Milled Orange Juice (<Emphasis Type="Italic">Citrus unshiu</Emphasis>) Powder

The aim of this work was to evaluate the degradation kinetics and stability of micro wet milled orange juice powders obtained by vacuum spray drying, using maltodextrin as a carrier agent. Powders were produced with four combinations of orange juice solids/maltodextrin solids 60:40, 50:50, 40:60, and 30:70 by weight. Ascorbic acid degradation, color, and antioxidant activity of powders were evaluated throughout 90 days. Powders were stored at 10, 25, and 35 °C and relative humidity of 33%. Temperature and storage time negatively influenced the stability of ascorbic acid and color, whereas antioxidant activity increased at the beginning of storage at a higher temperature then decreased slightly after 60 days. For stability study, powders were stored at different water activities (0.11 to 0.84) in order to determine the plasticizing effects of water on glass transition temperature. Both water activity and glass transition temperature were used to predict the critical conditions for storage. Vacuum spray dried powder produced with a ratio of 30:70 (orange juice solids/maltodextrin solids) was considered as the most stable, since it showed highest critical water activity (a_w?=?0.61) and lowest moisture content (0.11 g water/g of dry solid) among the four powders. Vacuum spray drying using superheated steam as the heating medium was proven to be an effective way of producing orange juice powders with minimum loss of nutrients.