`Valencia' oranges were-treated with an experimental polysaccharide-based coating, a commercial shellac-based water wax, or were left uncoated. The fruit were stored at 16 or 21C with 95% RH. Samples were periodically analyzed for internal gases, flavor volatiles, water loss, and `Brix. Coated fruit had lower internal O2 and higher CO2 and ethylene levels as well as higher levels of many flavor volatiles (including ethanol) compared to uncoated. The differences were greatest for shellac-coated fruit at the higher storage temperature. No differences were found for °Brix. The shellac-coating gave the best weight-loss control and the most restricted gas exchange. The low gas permeability characteristic of this type of shellac coating may result in altered flavor for fruit held at 21C.
Elizabeth A. Baldwin, Myrna O. Nisperos-Carriedo, and Jacqueline K. Burns
Albert Liptay, Jerry H. Stoller, and Ron Salzman
Root Feed is a product developed by Stoller Enterprises, Inc., to enhance crop productivity and quality. Weekly application of Root Feed in drip-irrigated crops was found to be the most effective frequency of application. Root Feed increased the number of the largest melons and total melons by over 50% and also increased fruit °Brix (soluble solids). Moreover, it was observed that a number of pests were suppressed with Root Feed, namely, whiteflies, a cucurbit virus, and downy mildew.
L. Antonio Lizana, Jorge M. Sandoval, Manuel Pinto, and Luis Luchsinger
An experiment was set up to elucidate the causes of differences in harvest time in the adjacent grape-growing areas of Rapel and Sotaqui in the Limari Valley, Chile. Berry samples of `Flame Seedless' were collected from each area, from 10 days after last GA spray until harvest (December to February). Soluble solids (SS), titrable acidity (TA), and SS/TA ratios were analyzed and days from full bloom to harvest, growing degree days, and ambient temperatures were recorded. In Rapel, full bloom was 25 Sept.; the harvest by 16 °Brix, started on 3 Jan., and the harvest by 20:1 SS/TA ratio (min. 15.5 °Brix) on 28 Dec. (11, 16, and 24 days earlier, respectively, than Sotaqui). Degree-days (DD) at harvest (16 °Brix) were 1058 in Rapel and 837 DD in Sotaqui. In the last 50 days prior to harvest, berry acidity was always lower in Rapel, decreasing from 0.87% to 0.47%, while in Sotaqui berry acidity decreased from 1.96% to 0.86%. From 20 Dec. to 2 Jan., the acidity did not decrease significantly (1.96% to 1.84%), but in the next 3 weeks decreased to 0.68%. This difference in the rate of acid degradation is related to the increase in minimum night temperatures in this same period of berry growth. It is concluded that the minimum temperature-dependent rate of organic acid degradation is the main factor influencing the SS/TA harvest index parameter.
P.R. Johnstone, T.K. Hartz, M. LeStrange, J.J. Nunez, and E.M. Miyao
Fruit soluble solids concentration (SSC) is an important quality factor for tomatoes (Lycopersicon esculentum Mill.) grown for processing. The use of drip irrigation often results in undesirably low SSC. The effects of late-season irrigation management on fruit yield and SSC was investigated in a series of drip-irrigated field trials in California from 2000–04. The effects of irrigation cutoff or deficit irrigation implemented 40 to 50 days preharvest (the period corresponding to the initiation of fruit ripening) were compared to a standard grower practice of irrigation cutoff 20 days preharvest. Irrigation cutoff 40 to 50 days preharvest increased SSC but resulted in substantial yield loss, with significantly reduced brix yield (Mg fruit solids ha-1). By contrast, deficit irrigation significantly increased SSC compared to the standard practice, with no significant loss of brix yield. In three commercial fields the effect of deficit irrigation on fruit SSC was investigated. Fruits were sampled on three dates: 1) 4 to 5 weeks preharvest, early-ripening, pink-stage fruit only, 2) about 1 week preharvest, both late-ripening, pink-stage fruit and early-ripening fruit now fully ripe, and 3) commercial harvest, composite of early- and late-maturing fruit. SSC increased in response to soil moisture stress induced by deficit irrigation, with late-maturing fruit as much as 1.6 °brix higher than fruit maturing before significant soil moisture stress. However, once a fruit reached the pink stage of maturity, its SSC was not affected by subsequent soil moisture stress. An additional five commercial field trials were conducted to compare growers' irrigation practices with greater degrees of deficit irrigation. In each field the grower's deficit irrigation regime was compared to a reduced treatment receiving 25% to 50% less water over the final 4 to 7 weeks before harvest. Across fields, applying 20% to 60% of reference evapotranspiration (ETo) over the fruit ripening period resulted in acceptable SSC without significant brix yield reduction. We conclude that deficit irrigation initiated during early fruit ripening provides a flexible tool for SSC management. Brix monitoring of earliest ripening fruit can help classify fields as to the severity of irrigation deficit required to reach desirable SSC at harvest.
Christopher D. Harlow, Elizabeth S. Larrea, and Mary M. Peet*
Research was initiated at the N.C. State Univ. Horticultural Field Laboratory, Raleigh, to identify cultural practices and tomato cultivars giving superior taste under North Carolina greenhouse conditions. The specialty cultivars `67', `Diana', `Elegance', `Momotaro', and `S630' were grown and harvested, as well as `Trust', which is grown on 85% of the North American greenhouse tomato acreage. Additionally, two fertilizer regimes were provided to the plants: standard greenhouse tomato fertilization (EC ≈1.75 dS·m-1) or high fertilization (EC ≈3.75 dS·m-1). Fertilizers were the same in both treatments. Seeds were started in October 2002 and transplanted, 2 per pot, into `Bato' buckets containing perlite in November. Standard cultural practices were followed, and plants were fertigated using the Harrow Fertigation Manager™ system. Taste tests conducted on three dates revealed differences among cultivars, with `67', `Elegance' and `Momotaro' consistently scoring well. Overall, all test varieties were scored higher than `Trust'; however flavor was somewhat less sweet than anticipated, especially early in the season, averaging 2-3 on a scale of 5, where 5 was “best”. No significant differences were seen between the standard and high fertilization treatments. Differences in total harvest weight were seen among cultivars. `Elegance' and `67' produced fruit consistently well through the harvest season, while the remaining cultivars' yields were sporadic. Harvested fruit were homogenized, and Brix was measured as an indicator of fruit quality. Significant differences in Brix were seen among the cultivars, with `67' significantly higher than all other varieties and `Elegance' and `Momotaro' higher than the remaining cultivars. All specialty cultivars had higher °Brix than `Trust'.
J. Brent Loy
Acorn squash (Cucurbita pepo L.) is one of the three major classes of squash consumed in North America. Breeding improvements over the past 30 years have focused on more compact cultivars, earlier maturity, darker rind color, and powdery mildew tolerance (PMT). Our observations from sampling acorn squash from local supermarkets at different times during the year show that eating quality is highly variable, and most often, not acceptable. Our taste tests indicate that for acceptable eating, quality acorn squash should have °Brix of 10 or higher, flesh %DW above 16, and a smooth, nonfibrous texture. Most commercial cultivars fail to meet the above minimum criteria for quality. Proper harvest time is a major determinant of squash eating quality. To obtain adequate °Brix levels, squash should not be harvested until at least 50 days after pollination (DAP). If squash are harvested between 25 to 40 DAP and then stored for two or more weeks, °Brix levels may increase to acceptable levels, but some mesocarp reserves will be remobilized to developing seeds, reducing mesocarp %DW and lowering eating quality. A major goal of the squash breeding efforts at the University of New Hampshire has been to increase mesocarp %DW for obtaining more consistent eating quality. We have evaluated several experimental PMT hybrids during the past 5 years, and in some of these, flesh DW has averaged 17% or higher, and eating quality has been rated consistently very good. The adoption of better quality acorn cultivars together with implementing proper harvest times and storage conditions could appreciably increase per capita consumption.
Jorge Siller-Cepeda, Manuel Baez-Sañudo, Rosalba Contreras-Martinez, Laura Contreras-Angulo, Rosabel Velez, and Dolores Muy-Rangel
Banana fruits `Cavendish' type were obtained from a warehouse at color green stage. At arrival, fruits were taken out of boxes, dipped into a thiabendazole solution for 5 minutes, dried at room temperature and separated into three lots. One lot was sprayed with Fresh Seal™ (FS) at 3 °Brix, a second lot was treated with Semper Fresh™ (SF) at 1.2%, and the third was left as a control. After that, all fruits were packed again inside the plastic bags within the original carton boxes. Film-coated and control fruits were ethylene treated for 24 hours at 150 ppm, and vented for 24 hours until they reached color 3 (more green than yellow). After that, film-coated and control fruit boxes were collected inside 238-L airtight containers to apply Smartfresh™ (SMF) treatments at 0 and 300 ppb for 12 hours at 22 °C, complementing six different treatments. Later, fruits were stored at 22 °C and 80% to 90% relative humidity for 5 days to follow up changes. Quality evaluations were registered every day, including weight loss, firmness, color, CO2, ethylene, pH, titratable acidity, °Brix, and sugar spots. SF alone and the combinations SF + SMF and FS + SMF reduced weight loss as compared with the other treatments. SMF alone or in combination with FS or SF maintained higher firmness and delayed yellow color development as compared with the other treatments. Combinations of SF or FS with SMF delayed and reduced the incidence of sugar spots as compared with control fruits. Chemical characteristics were not significantly affected by the treatments, but SF + SMF had higher acidity and a lower pH. All treatments reached between 20 and 21 °Brix after 5 days. The data show that combined treatments of SMF and film coatings reduce sugar spot incidence, improving appearance and extending yellow life of fruits.
Teri Hale*, Richard Hassell, and Tyron Phillips
Taste panel perception and preference of sweetness in three phenotypes (su, se and sh2) of sweet corn harvested at three maturities (early, mature and late) were compared to refractometer measurements and HPLC analysis of fructose, sucrose, and glucose. Panelist rating of sweetness and acceptability significantly correlated with HPLC analysis. These correlations were found for sucrose and total sugars present (for sweetness, r 2 = 0.70 and 0.61; acceptability, r 2 = 0.64 and 0.55). Sucrose significantly correlated with the total sugars present (r 2 = 0.95). The panelists' perception of flavor also correlated significantly with the amount of sucrose present and total sugars (r 2 = 0.66 and 0.59, respectively). Sucrose content was significantly different between se, sh2 and su, with sh2 having the highest level. Taste panels indicated this difference but showed not significant differnece between se and sh2 acceptablity. Su was only acceptable to panelists at early maturity. °Brix did not reflect the taste panels scores and HPLC measurements postively. Soluble solids and taste panel scores were negatively correlated in both the panel's perception of sweetness and acceptability (r 2 = -0.66 and -0.66, respectively) which indicates that as panel scores decreased °Brix increased. Comparison of soluble solids to HPLC analysis, indicate that °Brix was negatively correlated to sucrose and total sugar content, and that as soluble solids increased, the sucrose or total sugar concentration remained constant or decreased. Soluble solids measurements have been positively correlated with sucrose levels in other crops; but this was not the case with sweet corn.
O. Smith-Kayoae, V.O. Agbeja, A.O. Denton, and A. Aliyu
The development of a natural base for beverage products covers key steps including raw materials identification and sourcing, process development, product testing an market introduction. Agege 1 - a widespread sweet orange cultivar was compared with Parson Brown sweet orange type in the production of concentrated juice (approximate 30° Brix). Yield for Agege 1 was 14-16% while Parson Brown had 9-11% based on the processing modules adopted. Analysis of samples showed 40-110 millgram percent and 125-350 microgram percent for vitamins C and A respectively. Sensory testing revealed that concentrated juice for Agege 1 had superior appearance characteristics particularly in terms of color.
A muscadine vineyard planted at McNeil, Miss., in 1990 included 23 cultivars and a planting in 1992 included nine cultivars. Each entry was evaluated for eight useful traits over 4 years. The regressions of certain traits on others were performed to determine relationships that might be useful in selecting for valuable traits such as phyto-chemicals in seed. Ranges among cultivars for the traits were: harvest date—20 days, yield—33 kg per vine, berry weight—11.2 g, percent dry scar—38, °Brix—5, pH—0.5, seed per berry—1.2 and seed weight—5.5 g. The best relationship was between berry weight and seed weight.