Sensory Attributes and Volatile Components of Stored Strawberry Juice

Juices from three strawberry cultivars were stored at 2°C and 25°C for 6 wk and evaluated for the sensory attributes fresh strawberry, strawberry-jam, off-flavor, green, and sweet. Fresh flavor declined while off-flavor increased during storage, with the largest changes occurring at 25°C. Juice color and ascorbic acid also degraded much faster at 25°C. Fifteen volatiles were measured using headspace solid phase microextraction and gas chromatography. 2,5-dimethyl-4-hydroxy-3(2H)-furanone and 2,5-dimethyl-4-methoxy-3(2H)-furanone were positively related to fresh flavor and negatively related to off-flavor, while -terpineol was inversely related to fresh flavor. These volatiles explained almost 90% of the variation for fresh and off-flavor attributes.     

Stability of Non-Pasteurized, Refrigerated Muscadine Grape Juice

The stability of nonpasteurized muscadine grape juice processed with and without 100 mg/L potassium metabisulfite was monitored during storage at 3°C. The muscadine flavor intensity, sweetness, off-flavor levels, and color of white juices remained stable, and ethanol levels remained low for 7 wk. However, the flavor intensity and sweetness of nonsulfited white juice decreased, and off-flavor and ethanol levels increased after 7 wk. Sulfite lowered microbial levels in white juice throughout 9 wk. Red juices did not develop significant levels of off-flavors or ethanol during 9 wk, although the flavor intensity declined, especially in nonsulfited red juice. Sulfite lightened the color of red juice, but the color was stable in both sulfited and nonsulfited red juices.     

Influence of soil type and storage conditions on sensory qualities of fresh‐cut cantaloupe (Cucumis melo)

On‐farm cantaloupe (Cucumis melo) production as well as fresh‐cut storage duration can affect postharvest fruit sensory attributes. Both effects of soil type during production of cantaloupe fruits and storage temperature after fresh‐cut processing on sensory flavour and texture attributes were determined. Melons grown in sandy loam vs heavy clay soil were lower in sweet aromatic and sweet taste and higher in moisture release and fermented flavour. Fruity/melon, sweet aromatic, surface wetness, hardness and moisture release attributes decreased while fermented and sour flavour increased during storage regardless of soil type. During storage an increase in peroxidase activity occurred in fruits produced in sandy loam soil but decreased in fruits produced in clay soil. Clay soil appeared to have some advantages over sandy loam soil in producing cantaloupe fruits with better sensory quality attributes. Storage temperature conditions in this experiment (4 °C for 10 days or 4 °C for 4 days plus 10 °C for 6 days) did not have a statistically significant effect on these sensory attributes. Copyright © 2004 Society of Chemical Industry     

Sensory Characteristics of Cottage Cheese Whey and Grapefruit Juice Blends and Changes During Processing

Studies were conducted to determine the sensory characteristics of pasteurized blends of cottage cheese whey and grapefruit juice (0%, 25%, 50%, 75% and 100% whey), and the effects of processing alternatives and storage at 3°C. A trained sensory panel rated six attributes (grapefruit, sweetness, sourness, astringency, cheesiness, saltiness). Cheesiness and saltiness increased, while sourness, astringency, sweetness, and grapefruit flavor decreased as the percentage of whey increased. Protein removal did not affect the sensory characteristics, but vacuum stripping reduced cheesiness and increased grapefruit flavor and sweetness. Lactose hydrolysis increased sweetness and decreased cheesiness in blends with more than 50% whey. The flavor of most blends was stable for 14 wk at 3°C.     

Quality and Stability of Precut Mangos and Carambolas Subjected to High-Pressure Processing

ABSTRACT: Mangos were sliced, vacuum-sealed, and processed at 300 MPa or 600 MPa for 1 min. Fresh mango flavor declined and off-flavor increased during storage at 3 °C, but color, texture, and other sensory attributes changed very little. After 9 wk, the microbial levels in the control were 2 and 3 log CFU/mL greater than the 300 and 600 MPa treatments, respectively. Pressure treatments also slightly reduced fresh mango flavor and increased off-flavor and sweetness. Carambolas were sliced, vacuum-sealed, and processed at 600 MPa for 2, 4, or 6 min; at 800 MPa for 1, 3, or 5 min; or not treated. Samples were stored at 3 °C for 2 and 4 wk and color was evaluated after air exposure. All the 800 MPa treatments reduced browning compared to the control, but the 600 MPa was less effective.     

Changes in gastric resistance of Lactobacillus casei in flavoured commercial fermented milks during refrigerated storage

This study investigated the gastric acid resistance ofLactobacillus caseiin commercial fermented milks during refrigerated storage. Samples of fermented milks (natural, strawberry, fruits of the forest, vanilla and multifruits) were obtained from three different manufacturers. In vitro gastric acid resistance (GAR) was assessed in samples upon arrival to the laboratory and after 10 and 20 days of refrigerated storage at 5 °C and 12 °C. The GAR ofL. caseiin fermented milks may increase or decrease during storage in relation to the flavour and storage conditions. The occurrence of this phenomenon in commercial fermented milks containing probiotic bacteria may induce changes in their functionality after consumption.     

Fish Oil Dietary Effects on Fatty Acid Composition and Flavor of Channel Catfish

A typical channel catfish diet was supplemented with 0, 1.5, and 3% menhaden oil. Fillets were subjected to lipid, fatty acid, and TBA analyses. After 6 mo storage at ?18°C, fillets were again analyzed for TBA value and flavor panel profile. Fillets from catfish fed diets with 1.5 and 3% supplemental fish oil had elevated levels of n-3 fatty acids (P<0.05). TBA number and off-flavor attributes were not affected by treatments. Menhaden oil supplementation up to 3% enhanced the content of n-3 fatty acids in channel catfish fillets without adversely affecting flavor attributes or storage quality.     

Evaluations of Warmed-over Flavor during Chill Storage of Cooked Broiler Breast, Thigh and Skin by Chemical, Instrumental and Sensory Methods

Broiler breast, thigh and skin were cooked to 80°C, stored at 2°C for up to 5 days, and evaluated by chemical, gas chromatographic (GC) and sensory methods. Water and fat content of cooked meat did not change during storage. Thiobarbituric acid (TBA) values and levels of major headspace volatiles increased throughout storage time. Intensities of cardboard, warmed-over, rancid/painty, and overall off-flavor characteristics increased. Skin showed the least changes. Breast and thigh meat differed in GC profiles but were similar in sensory scores after 1 day and in TBA values after 2 days of storage. Both TBA and headspace GC measurements are associated with the off-flavor development.     

Changes in selected quality characteristics of minimally processed carambola (Averrhoa carambola L.) when treated with ascorbic acid

‘B 10’ carambola of ripening stage (RS) 3 and 4 were minimally processed (MP) and then dipped in 0, 15 and 30 mg L^?1 ascorbic acid (AA). The 1‐cm‐thick slices were then dried, packed into cling‐wrapped‐foam tray and stored at 7 °C for 0, 3 and 5 days. Skin colour (L*, C* and h°), flesh firmness, soluble solids concentration, vitamin C content, titratable acidity, pH, degree of browning, polyphenoloxidase (PPO) activity and sensory attributes of MP carambola treated with AA were determined. AA treatment had significant effect in decreasing cut surface browning degree but no significant effect on all the selected quality characteristics of the MP carambola. In the sensory evaluation, flesh colour, sweetness, flavour and overall taste were significantly affected by AA treatment especially at 15 mg L^?1. The RS of fruit significantly affected skin colour (C* and h°), pH and sensory attributes of colour and flavour of the MP carambola. As storage day (SD) progressed, skin colour (C* and h°), flesh firmness and vitamin C content, cut surface browning, PPO activity and all the sensory attributes of MP carambola decreased significantly. Flesh firmness of the MP carambola was affected by the interaction between AA × SD. Sensory attributes of MP carambola were affected significantly by AA × RS. All the sensory attributes of MP carambola positively correlated to each other but negatively correlated with browning degree. PPO activity positively correlated with browning degree. Copyright © 2007 Society of Chemical Industry     

Physical and chemical properties of chufa (Cyperus esculentus L) tubers grown in the Çukurova region of Turkey

Four lines of chufa (Cyperus esculentus) grown in 1998 and 1999 in the Çukurova region of Turkey were analysed for their physical properties, proximate chemical composition and fatty acid contents. The chufa lines contained on average (g kg^?1) 932.8 dry matter, 245.0 crude lipid, 256.8 starch, 14.3 ash, 50.5 protein, 89.1 crude fibre, 17.1 reducing sugar, 154.3 total sugar and 130.4 sucrose. Hunter L, a⁺ and b⁺ colour values of ground chufa samples were in the ranges 55.93–60.59, 3.71–5.09 and 15.60–16.85 respectively. Individual chufa tubers weighed between 0.224 and 0.283 g. The fatty acid composition of chufa oil included (g kg^?1) 689.2–732.9 oleic acid, 125.5–141.2 palmitic acid and 99.6–154.6 linoleic acid, which is comparable with that of olive oil. After storage for 1 year the differences in mean values were significant (p < 0.05). © 2002 Society of Chemical Industry     

Palatability and Storage Characteristics of Precooked Beef Roasts

The palatability and storage characteristics of fresh, frozen and precooked beef chuck roasts prepared using added phosphate-salt and vacuum cooking bags were evaluated. Palatability attributes (tenderness, juiciness, beef flavor intensity, and off-flavor intensity) of precooked roasts prepared in vacuum cooking bags with phosphate-salt were as good or better than freshly cooked roasts. Precooked roasts in vacuum cooking bags had the lowest total bacterial counts after storage for 14 and 28 days. A palatable precooked roast beef product was developed that can be stored for 28 days at 4°C.     

Compositional Changes in Mango Fruit During Ripening at Different Storage Temperatures

Chemical changes in Haden, Irwin, Kent, and Keitt mangos stored at 16-28°C and 85-90% RH were followed to determine the optimum storage and ripening conditions. Weight loss was slightly higher at 25° and 28°C than at 16-22°C. Breakdown in acidity during ripening was slower at 16°C. Vitamin C showed two basic trends; a general decrease as in Haden, Irwin, and Keitt or a steady increase as in Kent. Total and β-carotenoids were significantly higher at 22-28°C than at 16-20°C. No significant differences were observed with respect to carbohydrate and soluble solids content. However, sucrose increased spectacularly at all temperatures contributing most to the increase in sweetness. The pattern of chemical changes were strikingly similar in all the varieties. Temperatures of 20-22°C and 85-90% RH are recommended for storage and ripening of mangos to obtain sufficiently acceptable quality attributes.     

Monitoring the sensorial quality and aroma through an electronic nose in peaches during cold storage

BACKGROUND: The poor eating quality of fresh peaches transported to far markets is one of the main problems that fresh‐fruit exporting countries have to face. This research is focused on the evaluation of the sensorial quality, with emphasis on aroma, of four peach cultivars kept in long‐term storage, through maturity parameters, sensorial attributes and electronic nose (e‐nose) assessments. Fruits were stored at 0 °C and 90% elative humidity, for 14, 28 and 42 days. Evaluations were carried out after the fruit was taken out of cold storage and after a variable period of ripening at 21 °C, until flesh firmness reached 1–2 kgf. RESULTS: On fruit recently harvested, the e‐nose was suitable for discriminating among cultivars, even if it corresponded to an early pre‐climacteric phase. As cold storage proceeded, liking degree, and specially aroma, declined for each cultivar tested. Cultivars showed different behavior patterns for liking degree and especially aroma during cold storage. Flavor showed significant correlation with sweetness (r = 0.92), juiciness (r = 0.92) and texture (r = 0.93), but not with aroma and acidity, being these last ones being independent from each other. CONCLUSION: Post‐harvest storage life of peaches is limited by loss of quality. ‘Tardibelle’ peaches showed the highest quality attribute scores after 42 days of cold storage. This evidences the availability of commercial peach cultivars which are able to withstand long‐term storage periods, allowing far markets to be reached with high quality standards. Copyright © 2008 Society of Chemical Industry     

Deastringency of Persimmon Fruits by Creating a Modified Atmosphere in Polyethylene Bags

Removal of astringency from persimmons (Diospyros kaki L.) was achieved by enclosing the fruits in air-evacuated polyethylene bags. Reducing the initial in-package air volume created anaerobic conditions by decreasing the O₂ level. Induced anaerobic respiration in-creased the levels of CO₂. acetaldehyde and ethanol, in the atmosphere surrounding the fruit and thereby triggered the deastringency process. Deastringency in air-evacuated polyethylene bags was attained within3–4 days at 20°C. Following the deastringency, the fruits in the bags maintained a high quality and firmness during cold storage and shelf life. Good flavor was maintained for about 10 days at 20°C, but thereafter off-flavor developed due to accumulation of volatiles.     

The effect of thermal treatment on β‐glucosidase inactivation in vanilla bean (Vanilla planifolia Andrews)

The conditions for enzyme activity (pH and temperature) and kinetic parameters for the thermal inactivation of β‐glucosidase enzyme in vanilla beans have been investigated. The maximum enzyme activity was detected at pH 6.5 and 38 °C. The values obtained for V_max and K_m were 62.05 units and 2.07 mm, respectively. When hot water treatment (the most practical method of vanilla bean killing) was applied, β‐glucosidase treated at pH 6.0 and 60 °C for 3 min lost 51% of activity, while at 70 °C for 90 s the enzyme lost 60% of activity and at 80 °C for 30 s the enzyme lost 48% of its activity. When vanilla beans were cured in an oven at 60 °C for 36 to 48 h all β‐glucosidase activity was lost.     

Sensory characterisation and oxidative stability of walnut oil

This study was carried out in order to probe the extent of oxidative and flavour stability of walnut oil (WO) under conditions normally used for selling in retail markets, during a period of four months. Fresh WO was characterised by higher intensity ratings of nutty and oily film, and lesser ratings for pungent and astringent attributes. Low and similar values for sweetness and bitterness were also detected. The ratings for negative attributes (oxidised and painty) were close to zero. During the long‐term storage period, the extent of the oil oxidative degradation was more pronounced than flavour attributes deterioration. Peroxide values (PV), conjugated dienes and trienes increased significantly throughout the storage period, whereas tocopherol content and oxidative stability index showed significant reductions. Minor changes were observed in the overall flavour stability. Using a PV of 10 mequiv. O₂ kg^?1 oil as a quality criterion, WO stored in transparent glass bottles, exposed to fluorescent light (1100 Lux) and room temperature conditions, without addition of any antioxidant, could maintain an acceptable quality until two months of storage.     

Impact of Temperature Cycling and Isothermal Storage on the Quality of Acidic and Neutral Shelf-Stable Dairy Desserts Packaged in Flexible Pouches

The aims of the present study were, first, to identify the quality changes occurring in sterilized vanilla and strawberry pudding during storage at 20 °C; second, to understand the effect of storage temperature on aging; and, third, to determine if temperature could be used as an accelerating factor for shelf life or stability studies. Shelf-stable pudding was produced industrially and packaged in flexible pouches. Different ingredients were used to produce strawberry and vanilla pudding, and the resulting pH was 4.1 and 6.5, respectively. Pudding pouches were kept for 7 days at 20 °C and stored for up to 112 days at ??18, 4, 20, and 30 °C, or cycled repeatedly between ??18 and 20 °C, 4 and 20 °C, and 30 and 20 °C with a frequency of two cycles per week. Color, pH, apparent viscosity, flow behavior, and fluorescence spectra measurements were conducted up to 112 days of storage. The most relevant indicators to monitor quality changes in vanilla pudding were η, pH, b*, and tryptophan emission spectra, and in strawberry pudding, a*, b*, and riboflavin, tryptophan, and vitamin A emission spectra. Indeed, the temperature of 30 °C was identified as the most suitable accelerating factor for accelerated aging tests regarding changes in pH, color, riboflavin, and tryptophan fluorescence spectra of pudding, while cycles of 4/20 °C and isothermal storage at 4 °C were the most appropriate tests to accelerate changes in apparent viscosity of pudding.     

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.     

STUDIES ON PRESERVATION OF SUGARCANE JUICE

ABSTRACT

The variety CoP 92226 was selected for preparing sugarcane juice beverage on the basis of yield and sensory attributes from eight promising varieties of sugarcane. Sugarcane juice beverage samples were prepared by pasteurizing the sugarcane juice at 70°C for 10 minutes and adding citric acid (40 mg/100 ml), ascorbic acid (40 mg/100 ml) and potassium metabisulphite (150 ppm). Samples of sugarcane juice beverage were stored at room (30±5°C) and refrigeration (4±2°C) temperature in pre-sterilized glass bottles and analyzed for physico-chemical, microbiological and sensory attributes at every 15 days interval for 90 days. The pH, total soluble solids and total sugars decreased, whereas, titratable acidity and reducing sugars increased significantly (P<0.01) during storage. An appreciable increase in total plate counts and yeast and mold counts were observed, however, no coliforms, were detected in sugarcane juice beverage during storage. The changes in different attributes were significantly (P<0.01) higher at room temperature as compared to refrigeration temperature. The sugarcane juice beverage having citric acid and potassium metabisulphite showed minimum changes in sensory qualities during storage, both at room and refrigeration temperature. An acceptable quality beverage of sugarcane juice with satisfactory storage stability for 90 days at room as well as refrigeration temperature could be prepared.     

A comparative study of composition and postharvest performance of organically and conventionally grown kiwifruits

Postharvest performance of organic and conventional ‘Hayward’ kiwifruits grown on the same farm in Marysville, California, and harvested at the same maturity stage were compared in this study. Quality parameters monitored included morphological (shape index) and physical (peel characteristics) attributes of the initial samples. Maturity indices (CO₂ and C₂H₄ production, firmness, color, soluble solids content and acidity) and content of compounds associated with flavor and nutritional quality (minerals, sugars and organic acids, ascorbic acid, total phenolics, and antioxidant activity) were determined at 0, 35, 72, 90 and 120 days of storage at 0°C, and after 1 week of shelf‐life simulation at 20°C, after each storage duration. Organically and conventionally grown kiwifruits had similar soluble solids content at harvest, but conventional kiwifruits had a higher firmness and L* value, and a lower hue angle and chromaticity, resulting in a lighter green color when compared with the organic kiwifruits. These differences were maintained for all the storage durations, with the soluble solids content increasing more in conventionally grown kiwifruits. The two production systems resulted in different morphological attributes since organic kiwifruits exhibited a larger total and columella area, smaller flesh area, more spherical shape, and thicker skin compared to conventional kiwifruits. All the main mineral constituents were more concentrated in organic kiwifruits, which also had higher levels of ascorbic acid and total phenol content, resulting in a higher antioxidant activity. Sugars and organic acids composition was not affected by the production system. Copyright © 2007 Society of Chemical Industry