Firmness and colour of the fruit of some tomato cultivars from various sources during storage

The firmness of fruit of tomato cultivars Sonato, Grenadier, Adagio, Extase and Exquise obtained from growers was significantly different at time of harvest and after storage for 7 and 14 days at 19-23°C. However, all fruit had firmness values above 1000 g force on day 7 and above 700 g force on day 14, which are postulated minima for sale of fruit at retail level and use in the home respectively. There is no evidence to downgrade fruit of Sonato from a firmness point of view. Variation in fruit firmness within a sample was considerable for most cultivars on each testing date, and coefficients of variation were calculated to quantify this. Correlation coefficients between Hunter a/b ratio and firmness for the different cultivars ranged from -0.91 to -0.97. Regression lines relating a/b ratios to firmness fell into two groups. Firmness tests on samples of tomato fruit purchased from retailers suggested that all samples were adequately firm and had a firmness shelf-life of at least 7 days.     

PHYSICAL AND PHYSICOCHEMICAL CHARACTERISTICS OF THREE U.S. STRAWBERRY CULTIVARS GROWN IN THE PACIFIC NORTHWEST

Totem, Shuksan, and Puget Reliance are the three predominant strawberry cultivars in the U.S. Northwest. Fruit shape and size, volume, density, porosity, specific gravity, moisture content, water activity, color, firmness, pH value, titratable acid, and mineral content were determined. The three cultivars had significantly different physical and physicochemical properties (P < 0.05). Shuksan had the largest volume, and lowest density and specific gravity. The soluble solids and texture of Puget Reliance were the highest among the three cultivars. Totem had the highest ratio of soluble solids to total acids (SS/TA). Despite these differences, all three strawberry cultivars had attractive color, a high SS/TA ratio, and thus, good commercial qualities. These strawberry cultivars were also excellent sources of manganese, ranging from about 19% to 21% DRI (Dietary Reference Intake) manganese in 100 g fresh strawberries.     

Delayed harvest and cold storage period influence ethylene production,fruit firmness and quality of ‘Cripps Pink’ apple

The effects of harvest date and cold storage period on ethylene production, fruit firmness and quality of ‘Cripps Pink’ apple were investigated. Fruit were harvested from Perth Hills and Donnybrook (Western Australia) at commercial maturity (CM), 2, 4 and 6 weeks after CM prior to 0, 45, 90 and 135 days cold storage in 2003 and 2004. Delayed harvest significantly increased ethylene production, CIE values a* and C* at both locations in 2 years. Delayed harvest and extended cold storage period increased the internal ethylene production and reduced fruit firmness, soluble solids concentration: titratable acidity (SSC:TA) ratio and reduced CIE values L*, b*, h° during both years and locations. Fruit harvested 2 weeks after CM can be cold‐stored for 90 days with acceptable fruit quality. If the fruit is intended to be sold fresh immediately in local markets, the harvest can be delayed up to 6 weeks after CM to harness substantially improved fruit colour with acceptable fruit quality.     

Preference Mapping of Fresh Tomatoes Across 3 Stages of Consumption

Tomatoes (Solanum lycoperiscum) are a popular produce choice and provide many bioactive compounds. Consumer choice of tomatoes is influenced by flavor and visual appearance and external texture cues including hand firmness and sliceability. The objective of this study was to determine drivers of liking for fresh tomatoes across 3 stages of consumption. Seven tomato cultivars were ripened to a 6 on the USDA color chart. Trained panelists documented appearance, flavor, and texture attributes of tomatoes in triplicate. Tomato consumers (n = 177) were provided with knives and cutting boards and evaluated tomatoes across 3 stages: appearance (stage 1), slicing (stage 2), and consumption (stage 3). Consumers evaluated overall liking at each stage. Analysis of variance and external preference mapping were conducted. Overall liking was highest during the appearance portion of the test and lowest during the consumption portion (P < 0.05). Drivers of liking at stage 1 were color intensity, even outside color, and overall aroma. Drivers of liking at stage 2 were wetness/juiciness and overall aroma. Wetness/juiciness, seed presence, ripe flavor, and sweet and umami tastes were drivers of liking for tomatoes at consumption (stage 3). Four separate clusters of tomato consumers were identified. Cluster 1 preferred tomatoes with even color, higher color intensity, and flavor intensity. Cluster 2 preferred firm tomatoes. Cluster 3 preferred tomatoes that were soft and at peak ripeness; this cluster also had the highest liking scores for all tomatoes. Cluster 4 consumers generally consumed tomatoes in sandwiches rather than as‐is and preferred tomatoes with even and intense color. Tomato growers can utilize these results to target cultivars that are well liked by consumers.     

QUALITY EVALUATION OF MELON CULTIVARS. CORRELATION AMONG PHYSICAL-CHEMICAL AND SENSORY PARAMETERS

Soluble solid content, pH, firmness and color as measured by tristimulus colorimetry of nine cultivars of melon (Cucumis melo L.) were correlated with external appearance, texture and flavor. The Piel de Sapo type cultivars, RQ‐200 and Sancho, were the most appreciated for their external appearance, and MTV, a Rochet type cultivar, was preferred for its texture and flavor. ACL, a Yellow type cultivar, showed the highest pH and soluble solids (SS) content, while the Tendral type cultivars were the firmest. Flavor was positively correlated with pH and SS content, which confirms consumers’ preference for fruits with a high pH and high sugar content. The negative correlation between firmness and texture suggests that consumers prefer tender fruit. The colorimetric parameters served to differentiate three groups of cultivars as regards external color: Yellow type cultivars, Tendral type cultivars and Piel de Sapo and Rochet type cultivars. As regards internal color, none of the parameters clearly discriminated between the types of cultivars considered.     

A novel instrument to delineate varietal and harvest effects on blueberry fruit texture during storage

BACKGROUND: Firmness is an important quality index for blueberries. It is the major factor that determines consumer acceptability, storability and resistance to injury and diseases during storage and fresh marketing. Blueberry cultivars vary in their firmness, with southern highbush cultivars usually softer than Rabbiteye blueberries. In this study, varietal and harvest effects on blueberry firmness were measured by the Firmtech II and laser air‐puff instruments. This was the first time that the laser air‐puff, a non‐contact food firmness tester, had been used for firmness testing of small fruit, such as blueberry. RESULTS: Two southern highbush cultivars (Sweet Crisp and Emerald) and two Rabbiteye cultivars (Vernon and Savory) were used for varietal effect measurement, while a Rabbiteye cultivar (Premier) that was both machine and hand harvested was used for harvest effect observation. Fifty berry samples per replicate and four replicates were tested by two instruments at harvest and after 7, 14, or 21 days of storage. The laser air‐puff tester successfully delineated the difference in firmness due to cultivar characteristics and harvest methods, as well as the firmness loss over 21 days of postharvest cold storage (4 °C). The firmness index derived from the laser air‐puff tester achieved a significant correlation with the firmness values measured by the Firmtech (R² = 0.80). A new texture index, springiness, was developed from the laser air‐puff, which largely reflects the varietal differences in elasticity of fruit. CONCLUSION: This study demonstrated the efficacy of the laser air‐puff instrument for blueberry firmness measurement. This non‐contact instrument not only provides an alternative method of firmness measurement, but also offers a new index for fruit elasticity evaluation and better texture evaluation for blueberries. Copyright © 2011 Society of Chemical Industry     

Sensory Evaluation of High Vacuum Flame Sterilized Clingstone Peaches, Using Ranking and Signal Detection Measures with Minimal Cross-Sensory Interference

Seven peach varieties were canned conventionally with added syrup or added water and using high vacuum flame sterilization (HVFS) with and without added syrup. The treatments were assessed for sweetness, sourness, odor intensity, darkness of color, firmness by bite and firmness by visual appearance, using ranking and R-index measures. Cross-sensory interference was minimized by the excluding or reducing of the effects of inappropriate senses. Conventionally canned peaches were less firm to the bite but this did not correspond with visual appearance of firmness. Peaches canned with added syrup tended to be sweeter and less sour. Color and odor differences were less clear cut. Comparisons were also made with fresh peaches.     

Harvest parameters to optimise storage life of European plum 'Oullins Gage'

European plum ( Prunus domestica L.) cv. 'Oullins Gage' was harvested according to firmness on five harvest dates. Fruit was analysed at harvest and during storage for weight loss, firmness, total soluble solids (TSS), titratable acidity (TA) and skin colour before and after a 3-day shelf-life period at 20 °C. Significant differences were found among harvest dates in fruit mass, skin colour, firmness, TSS and TA. Fruit mass, TSS and colour b * increased, whereas firmness and TA decreased significantly during the harvesting period. Firmness parameter as a maximum maturity index and TSS:TA (or b * colour, a non-destructive measurement) as a minimum maturity index could be used to distinguish maturity at harvest. It is suggested that the best post-storage quality of 'Oullins Gage' plums would be obtained when fruit is harvested with TSS:TA >9 or b * colour >30, but with a firmness >20N to assure a long storage life.     

DEVELOPMENT OF POLYGALACTURONASE ACTIVITY AND SOLUBILIZATION OF PECTIN IN PEACHES DURING RIPENING

SUMMARY –Polygalacturonase activity, water-soluble pectin, total pectin, molecular weight distribution of water-soluble pectin, and fruit firmness were determined during ripening of freestone peaches. Polygalacturonase activity was not present in unripe peaches, but it developed during both tree and postharvest ripening. The development of activity paralleled the formation of water-soluble pectin characteristic of freestone peaches. Fruit firmness began to decrease before polygalac-turonase was detected, but the peaches softened rapidly after the appearance of the enzyme. Application of gel filtration revealed that the molecular weights of peach pectin range from about 100,000 to several million and decrease progressively during ripening. The results indicate a role for polygalacturonase in pectin solubilization during ripening of peaches.     

EFFECTS OF PRESTORAGE DRY AND HUMID HOT AIR TREATMENTS ON THE QUALITY, TRIGLYCERIDES AND TOCOPHEROL CONTENTS IN 'HASS' AVOCADO FRUIT

‘Hass’ avocado fruit were heated with dry (50% RH) or moist (95% RH) forced air at 38Cfor 6 h and then stored at 5C and 85% RHfor up to 8 weeks. Fruit were evaluated weekly for quality and for the content of three triglycerides and three tocopherols. Heated fruit had higher weight loss. The nonheated fruit and those heated with dry air displayed the best external quality. Fruit heated with dry air exhibited the best internal quality and the lowest chilling injury incidence. The respiration rate was more intense in fruit heated with moist air. Fruit firmness immediately after harvest was 51N, but decreased to less than 20 N at the end of the storage period in the three treatments. The analysis of triglycerides and tocopherols showed that the 1,2-Dilinoleil-3-Oleil-Glycerol and α-tocopherol were the most abundant compounds. Therefore, postharvest treatment with dry forced hot air before storage or transport reduces the incidence of chilling injury, and decreases quality deterioration in ‘Hass’ avocado fruit.     

Physicochemical changes during strawberry development in the field compared with those that occur in harvested fruit during storage

‘Chandler’, ‘Oso Grande’ and ‘Sweet Charlie’ strawberry cultivars were harvested at four stages of color development ranging from color break to full red and stored in the dark for 8 days at 1 °C. Changes in the physical and chemical characteristics of fruit during storage were compared with those occurring during development in the field. Strawberry fruit harvested at the three‐quarters colored and full red stages continued their development and ripening during storage. However, fruit harvested at the color break and half‐colored stages did not develop like those ripened in the field. Strawberries harvested at the three‐quarters colored stage developed the same pH, acidity, soluble solids, ascorbic acid and total phenolics content during storage as the at‐harvest levels present in strawberries harvested at the full red stage. In addition, three‐quarters colored strawberries were as firm and red after storage as the full red stage fruit were at the time of harvest. Thus, strawberries harvested at the three‐quarters colored stage can be stored for a longer period than strawberries harvested full red while retaining better color and firmness. Copyright © 2005 Society of Chemical Industry     

QUALITY ATTRIBUTES OF D'ANJOU PEARS AFTER DIFFERENT WAX DRYING TEMPERATURES AND REFRIGERATED STORAGE

Half-cooling times for hot (60°C) and cold (0°C) dried waxed pears in boxes, were identical and equal to 17 h. Waxed hot dried pears required an additional 21 h to equilibrate to holding room temperature. Waxing of pears modified the ripening pattern dependent upon whether the waxed pears were hot or cold dried. Waxed hot and cold dried pears exhibited lower external, but higher internal concentrations of CO₂ than nonwaxed fruit. After prolonged storage waxed cold dried pears required more time to develop the characteristic ripe yellow color and retained firmness longer than either waxed hot dried or non-waxed pears. Waxed hot dried pears were slower to develop yellow color and retained firmness longer than nonwaxed pears. Pears waxed immediately after harvest or after 90 days of cold storage demonstrated increased ripening time compared to nonwaxed fruit.     

Effect of Ozone on Postharvest Quality of Persimmon

ABSTRACT:  The effect of gaseous ozone exposure on the quality of persimmon picked at 2 different harvest dates was evaluated. Fruit from both harvests were continuously exposed to 0.15 ppm (vol/vol) of ozone for 30 d at 15 °C, 90% relative humidity (RH). Then, fruit were submitted to astringency removal treatment (24 h at 20 °C, 98% CO₂) and stored for 7 d at 20 °C (90% RH) in order to simulate shelf-life period. The most important disorder was flesh softening, which took place when fruit were transferred from 15 °C to shelf-life conditions. In the 2nd harvest, where the fruit were harvested with lower firmness, ozone maintained firmness over commercial limits even after 30 d at 15 °C plus shelf-life. Ozone-treated fruit showed the highest values of weight loss, coinciding with the maximum electrolyte leakage (EL) percentage. Ozone did not affect color index (CI), ethanol, total soluble solids (TSS), or pH. Unremarkable differences in acetaldehyde were observed between fruit submitted to ozone treatment and control fruit. No phytotoxic injuries in tissues were observed in ozone-treated fruit.     

FIRMNESS EVALUATION OF SWEET CHERRIES BY A TRAINED AND CONSUMER SENSORY PANEL

The objective of this study was to examine cherry firmness and the ability of a trained and consumer panel to differentiate between cherries of different firmness values. For the trained panel ( n =  12) and consumer panel ( n =  100) evaluations, two late-maturing, commercially important cherry cultivars were evaluated, "Selah" and "Skeena." For trained panel evaluations, the analytical firmness value of each cherry was determined, although for the consumer panel, cherries were characterized into different firmness categories (low, intermediate and high), after which, a series of paired comparisons were made. "Selah" was the less-firm cultivar by approximately 20 g/mm and consumers could distinguish the more-firm cherry in all comparisons ( P <  0.05). For "Skeena," consumers could only distinguish soft versus firm. Trained panelists were able to distinguish between cherries of a minimum analytical firmness value of ∼40 g/mm. A model was developed to predict sensory firmness from analytical determinations of firmness ( r =  0.63).

PRACTICAL APPLICATIONS

Developing prediction models to estimate sensory response from analytical data will benefit the fruit industry by potentially allowing the use of analytical measurements as a proxy for sensory evaluation. In addition, understanding the importance of firmness on cherry acceptance and knowing the specific firmness values at which individuals can perceive a difference in sensory firmness is useful for cherry growers to produce a cherry with acceptable texture.     

Quality changes during ripening of plums (Prunus domestica L.)

Quality changes during fruit ripening after the appearance of fruit colour of four Prunus domestica L. plum cultivars, ‘Jojo’, ‘Valor’, ‘Čačanska rodna’ and ‘Čačanska najbolja’, were investigated during 25 or 33 day periods. Fruit samples were analyzed for fruit weight, firmness, soluble solids content, fruit colour, content of sugars (glucose, fructose, sorbitol and sucrose), organic acids (malic, fumaric and shikimic acids), phenolics (neochlorogenic acid, p-coumaroylquinic acid, chlorogenic acid and rutin) and anthocyanins (cyanidin-3-rutinoside and peonidin-3-rutinoside). Ripening resulted in statistically increased fruit weight and soluble solids, decreased fruit firmness, darker colour of fruits, increased concentration of total sugars, decreased concentration of total acids, and increased concentration of anthocyanins. There was no influence of ripening on the content of phenols. The results show significant influences of cultivar on fruit weight, soluble solids content, firmness, fruit colour, concentration of total acids, SUAC index, concentration of total phenols and anthocyanins in European plums.     

EFFECT OF PHYSIOLOGICAL MATURITY AT HARVEST ON PEACH QUALITY DURING LOW TEMPERATURE STORAGE

Peaches (cvs ‘Loring’ and ‘Redglobe’) were collected from five packinghouses within a 20 km radius on a single harvest date. Using color chips to categorize harvest maturity, fruit color and firmness were evaluated on the day of harvest. After 7 day storage at 5°C, designed to simulate maintenance of a cold-chain during wholesale distribution, peach color, firmness and sensory quality were determined. Color and flavor development were inhibited at 5° C but the softening rate increased at increasing levels of maturity. Separation of softening from flavor and color development has implications in study of ripening physiology of the peach and in assessing current handling practices.     

CHARACTERISTICS OF FERMENTED NATTO PRODUCTS AS AFFECTED BY SOYBEAN CULTIVARS

The characteristics of four soybean cultivars, grown in the Northern plain region of the U.S.A. and harvested in different years were investigated. These soybeans were fermented into natto products. The characteristics of the intermediate and finished products were analyzed. Correlation coefficients among certain physical, chemical, sensory characteristics of raw soybeans, intermediate products and finished products were significant (P < 0.05). The ammonia content significantly correlated with firmness of the natto products made from these cultivars (r = 0.65). Minnatto and MN 91‐468 cultivars were similar to the Danatto cultivar in objective measurements and sensory properties. Compared with the other cultivars, Natto King had a higher solid matter content (1.92%) in the soaking water, a higher broken bean ratio (22.71%) after steaming and the hardest texture of the finished natto products. The effect of harvest year of Danatto cultivars and the quality attributes of the finished natto products varied with Bacillus natto strains.     

RESPONSE OF 'TOP RED DELICIOUS' APPLES TO DAMINOZIDE

Daminozide was applied at 2.2, 4.5, 6.7 or 9.0 kg/ha to ‘Top Red Delicious’ apple trees 86 days after full bloom the first year and at 2.2, 3.4 or 4.5 kg/ha, 80 days after full bloom the second year. At commercial harvest, after 2 and 4 months regular cold storage, and after 6 and 10 months of controlled atmosphere (CA) storage apples were evaluated for carbon dioxide, ethylene production, flesh firmness, external color, soluble solids, acids, subjective appearance and daminozide residue. Ethylene production was reduced as daminozide application was increased. Delay in onset of the climacteric ranged from 3 to 21 days depending on chemical rate used. Firmness, red color, acids, subjective appearance and number of days to reach climacteric were significantly improved by all rates of daminozide. Quality differences due to daminozide were evident following both types of storage. Daminozide residues were directly related to rate and did not dissipate during storage. There was no detectable daminozide carry-over in fruit from year to year.