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.
Morris Ingle and Edwin C. Townsend
Mervyn C. D'Souza and Morris Ingle
Superficial scald on apples is effectively controlled by the currently registered inhibitors, diphenylamine and ethoxyquin. However, the availability of these chemicals as scald inhibitors in the future is uncertain. There is renewed interest and need for scald research to develop prediction systems and non-chemical control measures. Scald is believed to be caused by the oxidation of α-farnesene into trienes. The reaction is partially inhibited by the presence of antioxidants in the peel.
We have developed a new method to evaluate scald reaction compounds. This method was used to show that differences exist in reaction compound concentrations between the blushed and nonblushed sides and scalded and normal portions of `Rome' apples. The benefits of this method over the conventional method will also be presented.
Morris Ingle, J.C. Morris, and M.C. D'Souza
Three types of soil were mixed with water containing DPA (2000 mg·liter-1) and benomyl (300 mg·liter-1) at 1% to 5% (w/w). `Rome' apples (Malus domestica Borkh.) were dipped in the mixtures over 8 days. The efficiency of DPA as a scald inhibitor was not consistently affected by soil type, soil concentration, or age of mixture. Chemical names used: methyl[1-[(butylamino)carbonyl]-1 H-benzimidazol-2-yl]carbamate (benomyl); diphenldyamine (DPA).
Mervyn C. D'Souza, Morris Ingle, and Suman Singha
Lycopene is the predominant carotenoid pigment in tomatoes and primarily responsible for red color. Spectrophotometric procedures for lycopene evaluation although accurate are time consuming and destructive. The objective of this study was to relate chromaticity values (L*,a*,b*) measured using a Minolta Chroma Meter CR-200b portable tristimulus calorimeter with lycopene concentrations in the pericarp of 'Celebrity', 'Mountain Delight' and 'Early Pick' tomatoes. Fruit were selected to encompass varying maturities from green to red ripe and were obtained from a commercial source. Lycopene from individual skin disks or pericarp plugs corresponding to each location of color measurement was extracted in acetone and measured spectrophotometrically at 503 nm. The L* value (a measure of lightness) or a* value (a measure of redness) was determined to be well correlated with lycopene concentration in all 3 cultivars. The linear regression of the lycopene concentration on the ratio of (a*/b*) provided the best R for all cultivars (0.75).
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.
Mervyn C. D'Souza, Suman Singha, and Morris Ingle
Chromaticity values (L*, a*, b*) of tomato (Lycopersicon esculentum Mill. `Celebrity', `Early Pick', and `Mountain Delight') were measured using a Minolta CR-200b tristimulus colorimeter. Lycopene concentrations in acetone extracts of skin disks or pericarp plugs were measured spectrophometrically at 503 nm. The L* or a* value was related to lycopene concentration in all the cultivars; however, the ratio of (a*/b*) provided the best R for all cultivars (0.75). These relationships allow the use of a portable colorimeter for rapid, nondestructive estimation of tomato fruit lycopene concentrations in laboratory or in situ studies.
Morris Ingle, Mervyn C. D'Souza, and E.C. Townsend
Firmness, soluble solids concentration (SSC), starch index (SI), internal ethylene concentration (IE), and titratable acid concentration (TA) of `York Imperial' apple (Malus ×domestica Borkh.) fruit changed linearly with harvest date between 152 and 173 days after full bloom (DAFB). Firmness was positively correlated with TA, SSC was correlated with SI, and SI was negatively correlated with TA. After 150 days of refrigerated-air (RA) storage, there was no relationship between DAFB at harvest and firmness or superficial scald, but the malic acid concentration declined linearly and storage decay increased linearly with DAFB. Firmness had declined to a plateau and was not correlated with any variable at harvest. Malic acid concentration after CA storage was correlated with DAFB, firmness, SSC, and SI; scald was correlated with firmness and SI; and decay was correlated with DAFB, firmness, SSC, and SI. During 150 days of controlled-atmosphere (CA) storage (2.5% O2, 1.0% CO2), firmness and TA decreased as a linear function of DAFB. Percentage of fruit with scald and scald rating changed quadratically with DAFB, and decay increased linearly with DAFB. After 150 days of CA, firmness was correlated with DAFB, SI, and IE at harvest; TA was correlated with DAFB, firmness, SSC, TA, and SI; scald was correlated with firmness and SI; and decay was correlated with DAFB, SSC, and scald index at harvest. During 250 days of CA storage, firmness, TA, scald, and decay changed linearly with DAFB in only 1 or 2 years out of 3. Formulas were created to predict firmness after CA within 10 to 12 N (2.0–2.5 lb-f) and TA to within 25%.
David M. Modise, Michael D. Glenn, and Morris Ingle
The split root technique was used to study water afflux in peach [Prunus persica (L.) Batsch] from wet to dry soil through root systems that bridge wet and dry soil. Peach trees conduct hydraulic lift (HL) to ameliorate water deficits in dry soil layers, under conditions of low transpirational demand. The objectives of this study were to examine the magnitude of HL in peach and to determine its effect on nutrient uptake from dry soil. In addition, the split root system was used to measure peach water uptake from soil supporting `Kentucky 31' tall fescue [Festuca arundinaceae (Schreb)] and determine the diurnal partitioning of water use from covered and bare soil treatments. A Scholander pressure bomb was used to record hourly measurements of water potentials (10 am to 4 p m), daily for a total of 14 days in 3 replicates (1 tree/rep.). Leaf stomata1 resistance was measured using a porometer, simultaneously with the water potential measurements. The CR 7 datalogger was used to record water transfer into the dry root section. 15N was applied in the 15-30 cm root zone, and the concentration in the leaves was determined using a mass spectrometer. Results obtained will be discussed in relation to objectives stated above.