aesthetic and from a quality-signaling perspective has an important function in consumer acceptability ( Steyn, 2012 ). Hence, peel color is an important quality attribute in determining consumer acceptance of apples ( Telias et al., 2011 ). The red color in
Esnath T. Hamadziripi, Karen I. Theron, Magdalena Muller, and Willem J. Steyn
Ignazio Infantino and Riccardo Lo Bianco*
Peel color is a critical index of external fruit quality and consumer appreciation level. Traditional methods for determination of peel color are based on visual analysis or punctual measurements by colorimeter. In this study we present a method based on digital image analysis that integrates the accuracy of an interactive measurement and the efficacy of an image analysis that descibes entire sides of the fruit. A sample of apple, mandarin, grape, and peach fruit was photographed (each fruit on two opposite sides) with a digital camera for determination of peel color. Digital images were converted from RGB to CIE L*a*b* format, and color characteristics were indexed and quantified. The implemented method uses a reference color image cropped from the best fruit (interactively chosen) to calculate a color index for each fruit of the image set. The final index is the weighted sum of the number of pixels of the fruit, where pixels closer to the reference color (distance in the CIE L*a*b space) are considered more relevant. This color index gives integrated information on fruit color quantity (% of cover color) and quality (hue and saturation). The method represents a rapid and efficient way of determining color of the entire fruit surface and overcomes difficulties and approximation of traditional methods. A modification of the same method can be used to determine peel rugosity (mandarin) and average size and number of grape berries per bunch.
Yiguang Wang, Chao Zhang, Bin Dong, Yaohui Huang, Zhiyi Bao, and Hongbo Zhao
Chinese flame tree (Koelreuteria bipinnata var. integrifoliola), a common ornamental tree in southern China, exhibits a variety of fruit colors among individual plants within the same cultivated field. In this study, 44 plants with different fruit colors were selected to investigate the impact of pigment composition on the coloration of fruit peels. The plants were divided into three groups based on the color phenotype of the fruit peel: red, pink, and green. The values of lightness (L*) were negatively correlated with redness (a*) and positively correlated with yellowness (b*). The correlations of chroma (C*) with the other color parameters differed among the three groups. In the pooled pink and red groups, C* was negatively correlated with both L* and b* and positively correlated with a*, whereas the opposite relationships were found in the green group. According to the pigment analysis, anthocyanins, chlorophylls, and carotenoids were detected in the fruit peels. Anthocyanins were found to be the main pigment responsible for the differences in fruit color among the various groups. The highest anthocyanin content of fruit peel was found in the red group, followed by the pink group; the lowest anthocyanin levels appeared in the green group. The major anthocyanin component in the fruit peels was identified as cyanidin 3-O-rutinoside. By classifying fruit peel color and determining pigment composition, this study provides a theoretical basis for further researching genetic control and regulation of anthocyanin biosynthesis genes on pigment accumulation and peel coloration of chinese flame tree.
Jacques R. Fouché, Stephanie C. Roberts, Stephanie J.E. Midgley, and Willem J. Steyn
research was to relate GS fruit position in the canopy and the respective light environments to external fruit quality in terms of peel color, sunburn, and red blush development under commercial fruit-growing conditions in South Africa. The peel color of
Huating Dou and Fred G. Gmitter
with 92% ± 3% RH. Fruit weight loss per treatment was investigated between day 1 and day 14, and peel color was measured at day 40. After fruit examination at day 90, fruit internal vitamin C, sucrose, SSC, and titratable acidity (TA) were determined as
R.C. Ebel, W.A. Dozier, B. Hockema, F.M. Woods, R. Thomas, B.S. Wilkins, M. Nesbitt, and R. McDaniel
This study was conducted to determine fruit quality of Satsuma mandarin Citrus unshiu, Marc. `Owari' grown on the northern coast of the Gulf of Mexico. Soluble solids increased linearly and titratable acidity decreased quadratically during October and November for the four sampling years. There was no significant interaction between sampling date and year. There was a significant year effect for titratable acidity, but not soluble solids or their ratio. A 10:1 soluble solids to titratable acidity ratio was observed on 10 Nov. Variation in fruit weight corresponded with cropload. Fruit weight increased during the sampling period due to an increase in fruit length since there was no change in width. Peel color was yellow-orange by 10 Nov., with many fruit still exhibiting patches of green color. Because of some green color present in the peel, the fruit would have to be degreened for successful marketing in U.S. retail chain stores.
Gene E. Lester and Michael A. Grusak
Commercially grown honey dew fruit [Cucumis melo (Inodorus group)] typically are harvested before abscission because fruit cut unripe have a longer storage life than fully ripe fruit. However, because fully ripe fruit contain higher concentrations of soluble solids (predominantly as sugars), an attribute that increases their preference among consumers, methods are being explored to extend the storage life of fully ripe fruit. In this study, fully abscised honey dew fruit were evaluated for tissue attributes and consumer preference following postharvest dipping in either chelated or nonchelated calcium (Ca) solutions. Calcium sources were an amino acid-chelated Ca, ethylene-diamine tetraacetic acid (EDTA)-chelated Ca, or calcium chloride (CaCl2), with each provided at three different rates. Fruit were evaluated at harvest, and after 14 or 22 days commercial storage. Evaluations were peel surface changes (color and disorders), hypodermal-mesocarp tissue Ca concentration, flesh firmness, soluble solids concentration, and consumer preference of the edible flesh. Peel color became yellowed and lighter during storage for all fruit, with higher Ca rates resulting in more intensely yellowed fruit. Hypodermal-mesocarp tissue Ca concentration was 0.90 mg·g-1 of fresh weight (900 ppm) at harvest, and declined in all fruit by 22 days storage. Peel disorders (disease and spotting) were none to slight for all fruit by 14 days storage, but by 22 days storage disease incidence ranged from none to severe, depending on the Ca source and rate. Fruit firmness declined in all fruit throughout storage, with the smallest declines measured in fruit treated with the amino acid-chelated Ca. Soluble solids concentration of fully ripe fruit was 12.3% at harvest, and showed either no decline or slight declines with storage among the treatments. Consumer preference was highest for freshly harvested fruit, but fruit were desirable even after 22 days storage across all treatments. Postharvest application of Ca at ≤0.16 m Ca in an amino acid-chelated form, versus EDTA-chelated Ca or CaCl2, slowed honey dew melon senescence so that after 22 days of commercial and retail storage the fruit were of high marketable quality, and there was no detrimental effect on consumer preference for the edible flesh.
Matthew W. Fidelibus, Karen E. Koch, and Frederick S. Davies
summer or fall to improve peel integrity and extend the harvest season ( Coggins, 1969 ; Fidelibus et al., 2002 ; McDonald et al., 1997 ). However, such applications also retard color break, and the resulting green peel color may delay harvest. Because
Luiz C. Argenta, Xuetong Fan, and James P. Mattheis
ethylene production were analyzed as described earlier ( Fan et al., 1999a ; Mattheis et al., 1998 ). Peel color was measured with a colorimeter (Minolta CR-200, Osaka, Japan) using CIE illuminant C and an 8-mm-diameter aperture. Color values a* and b
H.K. Wutscher and K.D. Bowman
Twenty-one selections consisting of 13 numbered hybrids, one ornamental, and seven named cultivars were tested as rootstocks for `Valencia' orange, Citrus sinensis L. Osbeck. The test included six, four-tree replications in randomized complete blocks on sandy soil typical of the center of the Florida peninsula. Trees propagated on Vangasay lemon, HRS 812 (Sunki × Benecke trifoliate orange), and HRS 942 (Sunki × Flying Dragon trifoliate orange) produced more fruit than trees on the other 18 rootstocks in the test. Trees on 10 rootstocks, including the widely used commercial rootstocks, Swingle citrumelo and Carrizo citrange, were intermediate in cumulative fruit production. Trees on five rootstocks, including Sun Chu Sha, Gou Tou #1, and Tachibana, had low yields and trees on HRS 939 (Flying Dragon trifoliate orange × Nakorn pummelo) and sour orange #2 were extremely dwarfed and were minimally productive because of tristeza virus disease. Fouryear cumulative fruit production ranged from 52 to 317 kg per tree. Fruit from trees on HRS 954 and HRS 952 (Pearl tangelo × Flying Dragon trifoliate orange) had the highest, and fruit from trees on Vangasay and Gou Tou #1 had the lowest total soluble solids concentration.