Quality Comparison of Hydroponic Tomatoes (Lycopersicon esculentum) Ripened On and Off Vine

There is a general belief that the quality of tomatoes ripened on vine is better than tomatoes ripened off the vine, influencing among other parameters, the price of this commodity. We compared the quality of hydroponic tomatoes ripened on and off vine by chemical, physical, and sensory evaluation to find what attributes are affected and to what extent. Lycopene, β-carotene, total and soluble solids, moisture content, ascorbic acid, acidity, pH, texture, and color were analyzed. Tomatoes ripened on vine had significantly more lycopene, β-carotene, soluble and total solids, higher a* and lower L*, and were firmer. However, a 100-judge panel rated only the color and overall liking of the vine-ripened tomatoes as more intense than the fruit ripened off vine. Therefore, the chemical and physical differences were mostly not large enough to influence the panelist's perception. The characterization of tomatoes ripened on and off vine may help to guide post-harvest handling and treatment and to improve the quality of tomatoes ripened off vine.     

Effect of storage conditions on the chemical attributes of Ogbomoso mango juice

Mango juices were extracted from Ogbomoso variety using the method of Brekke et al. (1972). Mango juices were packaged in polyethylene films, polyethylene tetraphthalate (PET or plastic) bottles and transparent glass bottles and stored at 6 °C, 26 °C and 34 °C. Percentage ascorbic acid loss, browning index, titratable acidity, pH and soluble solids were evaluated at 2-week intervals for 8 weeks. Percentage ascorbic acid loss, non-enzymatic browning and titratable acidity increased with storage time in all packaging materials. However, pH decreased with storage time and soluble solids remained constant. Higher percentage ascorbic acid loss, browning index and titratable acidity occurred in juices packaged in polyethylene film, than in PET and glass bottles. Percentage ascorbic acid, browning index and pH increased with increased storage temperature. However, titratable acidity decreased with increased storage temperature and soluble solids remained constant throughout the period of storage.     

THE INFLUENCE OF THE FIRMNESS OF RAW TOMATOES ON THE PHYSICAL, CHEMICAL AND SENSORY CHARACTERISTICS OF CANNED PRODUCTS

The effects of firmness of raw tomatoes on selected quality characteristics of canned products was the primary objective of this study. Firm fruits, as sorted with Holme's Vibratory Sorter, were found to be significantly (P≤ .05) higher in drained weight, Agtron E-5 color readings, total acidity, sodium hexametaphosphate-soluble, and sodium hydroxide-soluble pectic substances, and lower in pH, soluble solids, soluble solids/acid ratio, and water soluble pectin than soft and unsorted fruits. In determining the sensory quality, firm fruits were superior in flavor, texture, and overall quality but inferior in color compared to soft and unsorted fruits. This investigation revealed that sorting fresh tomatoes with a vibratory sorter and canning only the firm fruits had a positive impact on improving the quality of canned products.     

CONTROLLED ATMOSPHERE STORAGE AND EDIBLE COATING EFFECTS ON STORAGE LIFE AND QUALITY OF TOMATOES

Tomatoes at pink stage maturities were coated with Semperfresh^TM edible fruit coating which is composed of sucrose esters of fatty acids, sodium carboxymethyl cellulose and mono-diglycerides of fatty acids. One group of coated and uncoated tomatoes were stored at 23 × 2C under air atmosphere, another group was stored at 12C under air atmosphere and third group was stored at 12C, 93–95% RH in a controlled atmosphere (CA) containing 3% CO₂, 3% O₂ and 94% N₂. Samples of tomatoes were analyzed for firmness, weight loss, titratable acidity, pH, soluble solids, sugars, ascorbic acid and lycopene to examine changes in quality during storage. Semperfresh^TM edible fruit coating was found to be significantly effective at both storage temperatures (23 × 2C and 12C) in air to delay changes in firmness, titratable acidity, pH, soluble solids, sugars, ascorbic acid and lycopene. Semperfresh^TM fruit coating reduced fruit weight loss as compared to fruit without coating but the difference between coated and uncoated tomatoes was not significant. Shelf-life of pink tomatoes was increased 3 days at 23 × 2C and 6 days at 12C in air by coating. CA storage delayed compositional changes in tomatoes significantly as compared to air storage of coated and uncoated tomatoes. CA storage also had a significant potential for reducing weight loss and microbial spoilage. Tomatoes were stored 40 days in CA. Coated and uncoated tomatoes exhibited the same results in CA.     

Qualitative and nutritional differences in processing tomatoes grown under commercial organic and conventional production systems

ABSTRACT:  Organically grown products experienced a doubling in percent penetration of organic sales into retail markets during the period from 1997 to 2003; however, there is still a debate over the perceived quality advantage of organically grown fruits and vegetables. In a study focusing on commercial production of processing tomatoes, samples were analyzed from 4 growers with matched organic and conventional fields. For the 4 growers studied, individual analysis of variance results indicated that tomato juice prepared from organically produced tomatoes on some farms was significantly higher in soluble solids (°Brix), higher in consistency, and titratable acidity, but lower in red color, ascorbic acid, and total phenolics content in the microwaved juice. Results were significantly different among specific growers, and this may be attributed to differences in soil type and soil nutrients, tomato cultivar, environmental conditions, or other production-related factors. Higher levels of soluble solids, titratable acidity, and consistency are desirable for the production of tomato paste, in that tomatoes with these attributes may be more flavorful and require less thermal treatment. This has the potential to result both in cost savings from less energy required in paste manufacture and potentially a higher quality product due to less thermal degradation of color, flavor, and nutrients. Future work may involve a larger number of commercial growers and correlation to controlled university research plots.     

Degradation of quality attributes of sweetened Julie and Ogbomoso mango juices during storage

Changes in the quality attributes of sweetened Julie and Ogbomoso mango juices were investigated. Sweetened mango juices were processed, bottled and stored at 25 °C for 12 weeks. The titratable acidity, pH, total solids, ash, soluble solids and ascorbic acid contents were evaluated immediately after processing and subsequently at 2-week intervals. The L*, a* and b* (HunterLab) parameters were determined to evaluate colour changes due to non-enzymatic browning.Generally, the quality attributes of the sweetened mango juices decreased during storage. The titratable acidity, pH, total solids, ash, soluble solids and ascorbic acid contents decreased during storage. After 12 weeks of storage, the percentage ascorbic acid loss of sweetened Julie and Ogbomoso mango juices was 16.25 and 16.67%, respectively. Browning index, chroma and b* values increased during storage. Colour changes in sweetened mango juices were mainly due to b* value and chroma.     

COLOR QUALITY OF FROZEN STRAWBERRIES: EFFECT OF ANTHOCYANIN, pH, TOTAL ACIDITY AND ASCORBIC ACID VARIABILITY

SUMMARY— 40 lots of strawberries, consisting of 13 different selections and 5 varieties, were packed as frozen, sliced, sugared (4:1) fruit. Total anthocyanin content, the relative amounts of pelargonidin-3-glucoside and cyanidin-3-glucoside, ascorbic acid, pH, total acidity, soluble solids and Gardner L, a, b. determinations were made. After 9 months of storage, panel evaluation of the color quality and Gardner L, a and b determinations were taken. Results of correlation analyses indicated that pH was the only objective measurement having a high correlation with color quality. Neither ascorbic acid, total acidity nor soluble solids had significant correlations with color quality. From regression equation values, it was calculated that berries should have a pH of 3.51 or lower to have acceptable color after freezing. Anthocyanin content should be in the approximate range 450–700 μg/g to have acceptable color quality.     

Physico-chemical changes in Cavendish banana (Musa cavendishiiL var Montel) at different positions within a bunch during development and maturation

Studies on the physico-chemical changes between different hand positions (top, middle and bottom) within a bunch and different finger positions (upper and lower) within a hand at different maturity stages (between 3 and 15 weeks from the flower emergence) were carried out on ‘Montel’ banana (Musa cavendishii L). The suitable harvesting stage was found to be between 12 and 15 weeks after flower emergence. The size, weight, volume and peel colour of fruits increased significantly (P < 0·01) for fruits from all positions (hands and fingers within a hand) of the bunch until the end of maturity stage. On the other hand, texture values of the fruit decreased significantly (P < 0·01). The total soluble solids (TSS), ascorbic acid (AA) and sugar contents increased slowly during development, but the increase was rapid during ripening. The starch composition accumulated gradually (P < 0·05) at the early stages and decreased thereafter. The pH and titratable acidity (TA) values showed an irregular pattern in all the fruits from all positions during the maturity stage. However, significant differences were also detected in size, weight, volume, peel colour, texture, TSS, AA, pH, TA, starch and sugar contents between different hands and different fingers portions from the same bunch. © 1998 Society of Chemical Industry     

Effect of different packaging systems on the quality of tomato (Lycopersicon esculentum var. Rio Grande) fruits during storage

A packaging system is designed in our laboratory and evaluated for its suitability to extend storage life and improve the quality of tomato (var. Rio Grande) fruits at ambient temperature (Patent App. No. 484/2005). Freshly harvested mature green tomatoes were packed in polyethylene packaging with or without treating with calcium chloride, boric acid and potassium permanganate. The fruits were then evaluated for changes in quality parameters within the different stages of ripening. The treatments improved the storage life up to 96 days when compared with that of control (32 days). The results showed that within each ripening stage, the treated fruits remained better than that of control and all the ripening stages and treatments are significantly different ( P  < 0.05) from each other. It can also be deduced that treated fruits showed lower weight loss (%), total soluble solids (TSS) contents, acidity and spoilage incidence while ascorbic acid contents, sugar to acid ratio, flavour, texture, colour and overall acceptability were higher in treated fruits when compared with control at the red stage of ripening. Total sugars (%) were low in fruits treated with calcium chloride and boric acid with or without potassium permanganate.     

Effects of Chitosan on Yield and Compositional Data of Carrot and Apple Juice

Effects of chitosans on yield, titratable acidity, pH, soluble solids, and color of carrot and apple juice were evaluated. Carrots (Lange Rote Stumpfe) and apples (Golden Delicious) were treated with chitosan solutions (in 2% ascorbic acid) of two different concentrations and viscosities at 25°C between 0 and 120 min. The juices were obtained with a laboratory cage press following a standard program during 20 min. Treatments with chitosan produced no effect on juice yield but pH values and soluble solids were affected. Also chitosan treatment resulted in significant (P < 0.05) reduction of titratable acidity and color index. Reduction of β-carotene in carrot juice was also achieved and correlated with color index.     

Effects of Ultraviolet Light (UV‐C) and Heat Treatment on the Quality of Fresh‐Cut Chokanan Mango and Josephine Pineapple

The effects of ultraviolet (UV‐C) and medium heat (70 °C) treatments on the quality of fresh‐cut Chokanan mango and Josephine pineapple were investigated. Quality attributes included physicochemical properties (pH, titratable acidity, and total soluble solids), ascorbic acid content (vitamin C), antioxidant activity, as well as microbial inactivation. Consumers’ acceptance was also investigated through sensory evaluation of the attributes (appearance, texture, aroma and taste). Furthermore, shelf‐life study of samples stored at 4 ± 1 °C was conducted for 15 d. The fresh‐cut fruits were exposed to UV‐C for 0, 15, 30, and 60 min while heat treatments were carried out at 70 °C for 0, 5, 10 and 20 min. Both UV‐C and medium heat treatments resulted in no significant changes to the physicochemical attributes of both fruits. The ascorbic acid content of UV‐C treated fruits was unaffected; however, medium heat treatment resulted in deterioration of ascorbic acids in both fruits. The antioxidants were enhanced with UV‐C treatment which could prove invaluable to consumers. Heat treatments on the other hand resulted in decreased antioxidant activities. Microbial count in both fruits was significantly reduced by both treatments. The shelf life of the fresh‐cut fruits were also successfully extended to a maximum of 15 d following treatments. As for consumers’ acceptance, UV‐C treated fruits were the most accepted as compared to their heat‐treated counterparts. The results obtained through this study support the use of UV‐C treatment for better retention of quality, effective microbial inactivation and enhancement of health promoting compounds for the benefit of consumers.     

Antioxidant Capacity of Fruit Extracts of Blackberry (Rubus sp.) Produced in Different Climatic Regions

A range of blackberry genotypes harvested in different seasons and regions in Mexico (Michoacan) and in the United States (Pacific Northwest) were collected to determine their antioxidant capacity using oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) assays. Total acidity, ascorbic acid, soluble solids, total phenols, and total anthocyanins, as well as the correlation between all these parameters, were determined for all treatments. Total acidity ranged from 4.22% in wild blackberry from Patzcuaro, Mexico, to 1.02% in ‘Evergreen’ from Woodburn, Oreg. These treatments were also the outliers in terms of ascorbic acid content. Cultivar ‘Brazos’ did not exhibit any significant differences in acidity or ascorbic acid as a consequence of the geographic origin or harvest season. The highest concentration of soluble solids was recorded for ‘Evergreen’ from Woodburn and relatively low soluble solids levels were recorded for all the Mexican treatments. Wild blackberry from Patzcuaro exhibited the highest values for ORAC, FRAP, total phenolic and anthocyanin content. Other relatively high antioxidant capacity values were detected for ‘Marion’ and ‘Evergreen’, both produced in Oregon. Different cultivars grown in the same region/season consistently showed differences in antioxidant capacity. There was little effect of harvest season on phenolic levels. We conclude that levels of total acidity, ascorbic acid, soluble solids, antioxidant capacity, and polyphenols mainly depended on the genotype and not on the climate or the season. ORAC and FRAP values were both highly correlated with each other, and with total phenols and anthocyanin content.     

石榴-胡萝卜复合饮料理化性质、抗氧化活性及其货架期的研究

以石榴、胡萝卜为原料,按质量比1∶3、1∶1、3∶1混合配制石榴-胡萝卜汁复合饮料,研究常温(25±1)℃下60 d的储存期内其物理化学性质(pH值、可溶性固形物、总酸度)、抗坏血酸、总酚以及抗氧化活性的变化,并对复合汁进行感官评价。结果表明,3个样品的pH值分别为4.04、3.92和3.38,可溶性固形物分别为5.02%、6.14%和8.13%,总酸度分别为0.74、0.74 g/100 mL和0.77 g/100 mL,在60 d的货架期pH值有所降低,可溶固形物含量没有明显的变化,而总酸度有所增加。抗坏血酸含量以质量比为1∶3的混合汁占优,总酚含量、DPPH自由基清除率以质量比为3∶1的混合汁占优,3项指标在货架周期内呈总体下降趋势。质量比为1∶1的石榴-胡萝卜复合汁感官评价得分最高。     

Antifungal activity of chitosan and its application to control post‐harvest quality and fungal rotting of Tankan citrus fruit (Citrus tankan Hayata)

In this study, the antifungal activity of chitosan A (MW = 92.1 kDa) and B (MW = 357.3 kDa), with 94.2% N‐deacetylation were examined at various concentrations against fungi including Penicillium digitatum, Penicillium italicum, Botrydiplodia lecanidion and Botrytis cinerea. The effectiveness of these chitosans to control the post‐harvest quality of Tankan fruit, a popular sub‐tropical citrus fruit, was investigated. It was found that chitosan, depending on type and concentration, caused 25.0–90.5% growth inhibition on test organisms after 5 days of cultivation at 24 °C. Chitosan treatment significantly reduced (P < 0.05) the percentage decay of Tankan fruit during storage at 24 °C. After 42 days of storage at 13 °C, chitosan‐coated Tankan fruits were firmer, exhibited less decay and weight loss, and showed higher titratable acidity, ascorbic acid, and total soluble solids than the control fruit. Weight loss of Tankan fruits decreased as the concentration of chitosan was increased. On the other hand, chitosan A, regardless of concentration tested, was found to be more effective in retaining the firmness, titratable acidity and water content, total solid content and ascorbic acid content of Tankan fruits than chitosan B. Copyright © 2006 Society of Chemical Industry     

Effect of an Edible Nanomultilayer Coating by Electrostatic Self-Assembly on the Shelf Life of Fresh-Cut Mangoes

This work aims at evaluating the effect of an alginate-chitosan nanomultilayer coating, obtained by electrostatic layer-by-layer self-assembling, in the quality and shelf life of fresh-cut mangoes. Coated and uncoated fresh-cut mangoes were stored under refrigeration (8 °C) for 14 days. The changes in mass loss, titratable acidity, pH, ascorbic acid content, total soluble solids, malondialdehyde content, browning rate, and microbial count were evaluated during storage. At the end of the storage period, lower values of mass loss, pH, malondialdehyde content, browning rate, soluble solids, microorganisms’ proliferation, and higher titratable acidity were observed in the coated mangoes. The nanomultilayer coating did not improve the retention of vitamin C during storage of fresh-cut mangoes. Results suggest that chitosan-alginate nanomultilayer edible coating extends the shelf life of fresh-cut mangoes up to 8 days.     

Quality Changes in Tomatoes and Resistance to Alternaria Infection as Influenced by Varying Storage Temperature

Tomato fruits were stored at 27°C continuously or at temperatures of 35°, 18°, and 27°C for 3, 2, and 4 days, respectively, before inoculation with Alternaria solani. Following inoculation, fruits were ripened at 27°C for 6 days and evaluated for quality changes and response to infection. Decreased resistance occurred in fruits stored at varying temperature, resulting in significantly larger lesions. Surface color was not significantly affected by storage and inoculation. Firmness was only significantly affected in noninoculated fruits. The pH and titratable acidity improved significantly in control fruits. Total soluble solids was only different in noninoculated fruits. Reducing sugars were lower in inoculated fruits.     

Effects of Hypobaric Treatments on the Quality,Bioactive Compounds,and Antioxidant Activity of Tomato

Hypobaric treatment is becoming a potential technology to protect fruits from postharvest decay. The objective of this study was to investigate the effects of hypobaric treatments on storage quality, bioactive compounds, and antioxidant activity of tomato fruit. In this study, green tomatoes (cv. “Fen guan”) were treated with hypobaric pressures (0.04 and 0.07 MPa) at ambient temperature (20 ℃) for 28 d. The results showed that under hypobaric storage, the respiration rates significantly declined and the respiratory peaks postponed 12 and 8 d by 0.04 and 0.07 MPa treatments, respectively, compared to control. Total soluble solid, titratable acidity, ascorbic acid, and lycopene were retained by hypobaric treatment. Moreover, ascorbic acid contents treated with 0.04 and 0.07 MPa were, respectively, 37% and 26% higher than control at day 24 and the contents of total polyphenols were, respectively, 1.28 and 1.11 times higher than control. Production and accumulation of toxic substances were significantly restrained. The ethanol content decreased, respectively, by 53% and 84% than control. At later storage period, the superoxide dismutase activity in treated fruits was about 0.58 U/(g·FW·min), whereas only 0.29 U/(g·FW·min) in control. Hypobaric treatment not only maintained a high activity of superoxide dismutase and peroxidase (POD), but also improved antioxidant capacity. All the results indicated that hypobaric treatment was a potential helpful method to protect the quality and nutrition of tomato and prolong ripening of tomato. Furthermore, the effect of 0.04 MPa hypobaric treatment was found better than 0.07 MPa.     

Shelf-life extension of peaches through sodium alginate and methyl cellulose edible coatings

The objective of this study was to determine the effect of sodium alginate and methyl cellulose coatings on the respiration rate, firmness, acidity, pH, total soluble solids and desiccation rate of peaches. Coated and uncoated control fruits were stored at 15 °C and 40% RH. Respiration rate, moisture loss, and changes in firmness, total titrable acidity, pH and total soluble solids of coated and control samples were determined at 3‐day intervals. The respiration rate, moisture loss and changes in quality parameters were much lower in coated peaches as compared with the control. While the maximum acceptable shelf‐life at 15 °C for control samples was 15 days, the coated samples maintained their acceptability up to 21 and 24 days, respectively, with sodium alginate and methyl cellulose coating. The reduced respiration and transpiration rates as a result of coatings were considered responsible for maintaining the quality and increasing the shelf‐life of peaches.     

Potential isotopic and chemical markers for characterising organic fruits

Several isotopic (¹³C/¹²C, ¹⁵N/¹⁴N, ¹⁸O/¹⁶O, ²H/¹H, ³⁴S/³²S) and chemical–physical parameters (pH, fruit weight, juice yield, titratable acidity, total soluble solids, skin resistance, flesh firmness, colorimetric characteristics, weight loss after harvesting, antioxidant activity, earliness index, total nitrogen, ascorbic acid, synephrine, anthocyanins and polyphenols, citric acid, malic acid, sucrose, glucose and fructose content) were investigated as potential markers of organically cultivated oranges, clementines, strawberries and peaches produced in Italy between 2006 and 2008, in experimental fields and in certified farms. The ratio ¹⁵N/¹⁴N, ascorbic acid and total soluble solids were shown to be the most significant variables for distinguishing between organically and conventionally cultivated fruits. It was not possible to define general threshold limits typical of organic fruits because these parameters are influenced also by fruit specie, cultivar, year and site of production. Combining isotopic and chemical markers a good discrimination between organic and conventional fruits of different species was achieved.     

Effects of sucrose polyester coating on fruit quality of apricots (Prunus armenaica (L))

Mature apricots were coated with different concentrations of a mixture containing sucrose polyesters (Semperfresh(tm) fruit coating) to determine the effect of that coating on shelf-life, post-storage life and quality of apricots. Respiration rates, weight loss, colour change, variations in soluble solids, ascorbic acid content, titratable acidity and pH of apricots were effectively reduced by both the 10 g litre^?1 and 15 g litre^?1 concentrations during ambient storage. After 10 days of cold storage both concentrations caused firmer fruit, higher pH, titratable acidity, soluble solids and ascorbic acid.