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L.J. Grauke, T.E. Thompson, and E.F. Young Jr.

The Munsell system of color notation was used to study differences in kernel color arising between four pecan cultivars (`Cheyenne', `Choctaw', `Western', and `Wichita') grown at four locations (Tulare, Calif., and Brownwood, Crystal City and El Paso, Texas) during two seasons (1987 and 1988) and were stored under different temperatures (ambient and frozen). The hue, value, and chroma of pecan kernels varied significantly in the 2 years of the test. Kernels collected in 1987 were more yellow and lighter and had greater color saturation than kernels collected in 1988. Cultivars differed in hue, value, and chroma at the initial color determination. `Cheyenne' kernels were the most yellow (hue of 18.8) and were the lightest (value of 6.4) of any cultivars tested. `Wichita' kernels were more intensely colored (chroma of 4.7) than `Cheyenne' or `Choctaw' kernels. Kernels from pecan trees in El Paso were more yellow than those from other locations and were lighter than kernels from either Brownwood or Tulare, Calif. Kernels evaluated after being frozen 6 or 12 months could be distinguished from fresh kernels on the basis of hue. Frozen samples were more red than fresh kernels. Kernels frozen 12 months were less intensely colored than fresh kernels or those frozen only 6 months. There was a significant linear relationship between time in the freezer and each color attribute. Hue and chroma were negatively correlated with storage time, while value was positively correlated.

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Juan C. Díaz-Pérez, Dan MacLean, Smiljana Goreta, Sarah Workman, Erick Smith, Harwinder Singh Sidhu, Gunawati Gunawan, Anthony Bateman, Jesús Bautista, William Lovett, Maja Jukić Špika, Gvozden Dumičić, and Mira Radunić

(blue) to +b (yellow). Chroma (C*) [(a* 2 + b* 2 ) 1/2 ] and the hue angle (h°) values (0° = red-purple; 90° = yellow; 180° = blue-green; 270° = blue) were calculated from the a* and b* values ( McGuire, 1992 ). Chemical attributes. A juice sample was

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Judith Zambrano, Sagrario Briceño, Lidis Pacheco, and Clara Méndez

`Palmer' and `Keitt' mangoes (Mangifera indica L.) were treated with two commercial wax coatings. The fruit were placed in 20-liter plastic containers, stored at 5C, and 85% to 95% relative humidity. Fruit were dipped fully in 1% aqueous suspensions of Pro-long and Primafresh C (original concentration) and analyzed at 2-day intervals for 18 days, with day 0 being 24 h after harvest. The following parameters were monitored: peel and pulp color (L*, chroma, and hue), fresh weight loss, total soluble solids, and titratable acidity. Both waxes reduced the rate of loss fresh weight of mangoes as compared with uncoated fruit. No differences were found for titratable acidity and total soluble solids. Waxed fruit were lighter (higher L* values) and less intense (lower chroma values) in color than control fruits.

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Tommy E. Thompson, L.J. Grauke, and E.F. Young Jr.

The Munsell Color System was used to define pecan [Carya illinoinensis (Wangenh.) K. Koch] kernel colors and color changes for 21 clones, 11 locations, and 4 storage methods for nuts collected over a 4-year period. Hue readings ranged from 10.0 (10 red) to 22.5 (2.5 yellow). Value readings ranged from 2.5 to 8.0, and chroma readings ranged from 1.0 to 8.0. A total of 91 color chips (individual combinations of hue, value, and chroma) were needed to describe kernel color variability. In 1987 and 1988, one color [15.0/5/4 (hue/value/chroma)] accounted for 3,979 of the 32,078 readings taken, and the 15 most common colors accounted for 80.7% of all the readings. The Munsell system of color determination was well suited for pecan color determinations. A simplified color rating system with only six color classes was developed for general use by the pecan industry. This system is also routinely used in our breeding and genetics program to define this very important quality trait in pecan.

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Morris Ingle and Edwin C. Townsend

Firmness, total soluble solids (TSS), starch concentration (starch index, SINDEX), and surface color (L*, a*, and b*) were measured for 18 `Delicious' apple strains (Malus ×domestica Borkh.) produced in a replicated, randomized planting at the West Virginia Univ. Experiment Farm, Kearneysville. There was a significant difference between 1991 and 1993 for firmness, L* on the blush or outer side (BL*), Bb*, BChroma, a* (nonblush side), hue angle, and Chroma. There were significant differences between strains in firmness and chromaticities and their derivatives, but not TSS or SINDEX. All measurements changed linearly with days after full bloom (DAFB). There were large chromaticity differences between the two sides of the fruit 130 DAFB, but the nonblush side changed more than the blush side, resulting in little difference at 158 DAFB. BL*(Ba*/Bb*) and L*(a*/b*) produced better separation of strains and sides than did Chroma, although the products were significantly correlated with hue angle and Chroma. The nonblush side of `Delicious' fruits should be monitored to obtain the highest percentage of fruit in the highest grades.

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J.G. Diaz and J.E. Manzano-Méndez

Lulo (Solanum quitoense L.) fruits grown at the Andes farms, T·chira State in Venezuela, were harvested at the mature green stage, selected, washed, and transported to the postharvest Lab. Fruits were stored in small commercial carton boxes in storage rooms at 5, 10, and 15 °C during 3 weeks. Chemical parameters such as solid soluble concentration (SSC), pH, tritatable acidity (TA), ratio SSC/TA, and physical parameters such as Color: L*, Hue, Chroma, color index (a+b)/L × 100, texture and fresh fruit weight loss (FFWL), in pulp extract and from the whole fruit were analyzed at the initial and at the end of each storage week. These characteristics ranged in the fellowing way: SSC: 749% ± 8.09% and its media of 8.02%, TA: 1.05%–1.18% for temperature and 1.01–1.27 for storage time with an average of 1.16% (expressed as citric acid), color index: 4.54–5.22 for storage time and 4.30–5.13 for storage temperatures with an average of 4.86, chroma: 6.21–6.63 for storage time and 6.00–6.55 for storage temperatures with an average of 6.36, FFWL: 1.30%–1.44% for storage temperature and 0.67%–2.11% for storage time .The SSC decreased with increasing the storage temperature. The TA, color index, and chroma decreased with the storage time and increased with storage time, the FFWL values increased with storage temperatures and with storage time.

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J.E. Manzano-Méndez and J.G. Diaz

Tamarillo (Cyphomandra betacea L.) fruits, grown in the Venezuela Andes farms, were harvested at mature-green stage, graded, selected, washed, and transported to the posharvest lab. for analysis. Fruits were stored into plastic containers in storage rooms at (5, 10, and 15 °C for 3 weeks. The soluble solid concentration (SSC), pH, tritatable acidity (TA), ratio SSC/TA, color: L*, Hue, Chroma, color index (a+b)/L × 100, texture, and fresh fruit weight loss (FFWL) in pulp extract and in the whole fruit were determined on the first day of harvest and at the end of each storage week. These parameters ranged as follows: SSC: 7.92–8.84%, pH: 4.06–4.35, TA: 1.14%–1.21% (expressed as citric acid), SSC/TA: 1.58–1.75, Chroma 42.72—45.54, FFWL: 0.83% at the second storage day to 4.39% at the 3rd storage week. Also, FFWL was 1.03%–1.40% for 10 and 15 °C, respectively. Fruits stored at the highest temperature increased pH values, the TA decreased with stored time, the Chroma and FFWL values increased with the increasing temperature and storage time.

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Chen-Yi Hung, Cindy B.S. Tong, and John R. Murray

The color of red potatoes is due to an accumulation of anthocyanins in periderm tissues. The objective of this study was to examine the effect of several factors on tuber redness. Using the red tuber-producing S. tuberosum ssp. tuberosum cultivar Norland, we observed that chroma (intensity of redness) and anthocyanin content of greenhouse-grown tubers decreased as tuber weight increased. There was a slight or no increase in hue (tint). We used HPLC to determine that pelargonidin and peonidin are the major anthocyanidins (aglycones of anthocyanins) in tuber periderm. The ratio of pelargonidin to peonidin increased as tuber weight increased up to 25 g fresh weight. The decrease in chroma was not due to an increase in cell sap pH; we observed a decrease in cellular pH as tuber weight increased. Controlled-atmosphere storage had no effect on tuber chroma or anthocyanin content compared to air storage. Methyl jasmonate, sucrose, or light treatment did not increase anthocyanin accumulation. Tubers exposed to light had less anthocyanin than those kept in the dark. We are examining the developmental expression of anthocyanin biosynthetic genes, as well as the effect of maize transcription factors on anthocyanin synthesis, in tuber periderm.

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Mervyn C. D'Souza, Morris Ingle, and Suman Singha

Chromaticity values (L*, a*, b*) of `Rome Beauty' apples (Malus domestics) were measured at weekly intervals during maturation periods in 1988 and 1989. Chromaticity was measured using a Minolta Chroma Meter CR-200b calorimeter on four quadrants of the fruit at locations midway between the stem and calyx ends. The apples continued to develop red color through the maturation period. After storage, the peel areas where chromaticity was measured were evaluated for scald intensity. The L* value at harvest was correlated positively with scald intensity, while the a* value was correlated negatively. An equation has been developed to describe the relationship between chromaticity values at harvest and scald intensity after storage.

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Monika Schreiner, Angelika Krumbein, Ilona Schonhof, Stefanie Widell, and Susanne Huyskens-Keil

A new approach for nondestructive quality assessment based on color measurement was developed for red radishes (Raphanus sativus L.). Postharvest changes in hue angle corresponded with changes in soluble and insoluble pectic substances linked to textural characteristics in `Nevadar' radishes. Changes in glucosinolates were related to changes in chroma and were associated with radish flavor. However, monosaccharides were not related to root color during the 4 days of postharvest period. Nevertheless, the data suggest that root color may be used as a rapid, inexpensive and reliable indicator of quality during the postharvest distribution of radish.