首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 218 毫秒
1.
Worldwide the USA is the largest user of flax fibre, though very little is actually grown or produced in the USA. ‘Ariane’ flax was grown in 1990–1991, 1991–1992 and 1998–1999 in South Carolina, USA and evaluated for production characteristics. Plots (15 m long and 2 m wide) in the fall of 1990 and 1991 generated dry matter plant yields ranging from 4510 (early harvest at a seeding rate of 67 kg ha?1) to 7340 (late harvest at a seeding rate of 134 kg ha?1) kg ha?1. Based on these results, seed was sown on a private farm using a drill in 19 cm rows at a seeding rate of 101 kg ha?1 in 1998–1999. Early harvest, selected for optimal fibre quality, produced a dry matter plant yield that averaged 4076 kg ha?1. Late harvest, selected to optimise seed plus fibre, produced a dry matter plant yield that averaged 5076 kg ha?1. Stubble remaining in the field after mowing at about 6.0–7.6 cm above the soil surface resulted in a fibre loss of about 3% of total plant dry matter or 10% of potential total fibre yield. Dry matter and fibre yields suggested that flax could be produced in the southeastern USA using traditional farming methods for the area. Copyright © 2004 Society of Chemical Industry  相似文献   

2.
本研究以‘红阳’猕猴桃为研究对象,通过对不同成熟度果实催熟后的指标分析,明确采用外源乙烯催熟 实现猕猴桃早采上市的适宜采收期,并进一步探讨了乙烯添加量和温度条件对催熟效果的影响。结果表明:只有当 猕猴桃达到一定成熟度(干物质质量分数大于17%)时,催熟软化后的果实才可被消费者接受,可实现猕猴桃的早 采错季销售;采用25~100 μL/L添加量的乙烯催熟(20 ℃)‘红阳’猕猴桃,3~5 d即可完成快速软化,且不同添 加量处理间可溶性固形物和可滴定酸质量分数无显著性差异,温度是影响乙烯的催熟作用重要因素,在较高温度 (20 ℃)下,乙烯催熟可明显缩短软化进程。  相似文献   

3.
Abstract Response of white‐fleshed peaches (‘Sugar Lady’, ‘Snow Giant’, ‘White Lady’and ‘Snow King’) and nectarines (‘Arctic Queen’and ‘Arctic Rose’) to controlled‐atmosphere (CA) storage is cultivar dependent. Samples of fruit of these six cultivars were collected just prior to commercial harvest and held in either regular‐atmosphere (RA) storage at 1C or controlled‐atmosphere (CA) storage at 2% O2 and 6, 12 or 18% CO2, all at 1C. Four of the six cultivars (‘Snow Giant’, ‘White Lady’, ‘Snow King’and ‘Arctic Queen’) displayed excessive internal browning and poor flesh color after only 30 days of storage and should not be considered for long storage (+30 days). While ‘Sugar Lady’and ‘Arctic Rose’performed better and are possible candidates for CA storage, they should not be stored more than 45 days after harvest. The value of CA storage to extend the marketing of white‐fleshed peaches and nectarines is questionable at best. If CA storage is to be used for storage‐life extension of white‐fleshed peaches and nectarines, O2 level should be maintained at 2% or less and CO2 level maintained at 12% or higher.  相似文献   

4.
A study was carried out in Eastern Province, Kenya to evaluate whether the harvesting of cowpeas at different times and intercropping with maize were effective in reducing field infestation by storage bruchids.

Cowpea seed harvested very late (4 weeks after the recommended harvest time) was infested by storage bruchids to a significantly greater extent than cowpeas harvested early or at the recommended harvest time. The intercropping experiments showed that bruchid infestation was significantly reduced in the intercropped cowpeas. These results are discussed in view of the current cowpea farming systems in Kenya.  相似文献   


5.
Flavonoids are important in plant interactions with the environment and may have positive effects on human health. Effects of light quality and quantity on flavonoid concentration were studied in baby spinach (Spinacia oleracea L.) cultivated under three types of shade netting differing in transmittance of UV‐B and PAR, at two times during the season. Leaves harvested at two growth stages for each sowing were subjected to different post‐harvest storage conditions. Shade nettings had a relatively small effect on flavonoid concentration in baby spinach. The largest effect was found when radiation was most intense. The nettings then decreased total flavonoid concentration by 15–24% at the normal commercial growth stage at harvest. Radiation and plant growth both affected flavonoid concentration, in opposite or similar directions depending on time of season. This variation was reflected in the statistical analysis, showing significant interactions among the factors. There were large differences (up to 100%) in flavonoid concentration between the different times of the season, in shaded as well as unshaded spinach. Flavonoid concentration and composition changed during storage, but no consistent difference was found between the shaded and unshaded leaves. In most cases, total flavonoid concentration increased significantly during the first 6 days of storage. In conclusion, the use of shade netting is acceptable for production of baby spinach as regards flavonoid concentration and composition. Copyright © 2007 Society of Chemical Industry  相似文献   

6.
The influence of two different harvest times (optimal and 4 days earlier) on thirty flavour compounds, titratable acid and sugars as well as consumer acceptance of four old and endangered tomato cultivars (‘Ananas’, ‘Auriga’, ‘Green Zebra’ and ‘Lukullus’) was analysed. In most cases, cultivar type had a greater effect on the volatiles profile than harvest times. Sugar contents were mostly higher at optimal harvest compared with early harvest, whereas acid content was in most cases not affected by harvest time. Consumers perceived differences in several visual and sensory aspects between cultivars as well as harvest times. The optimal harvest was regularly preferred to or at least regarded as equal to the early‐harvest time. Sensory evaluation was poorly related to the aroma volatile profile and only partly to the acid and reducing sugar contents of tomatoes. This was probably owing to the special external characteristics of the tomatoes: differing in size, shape and colour from the ‘normal’ red types.  相似文献   

7.
The present study was undertaken to develop a protocol to screen bean germplasm for the hardshell character, evaluate the effect of hardshell on cooking time and study the relationship between hardshell and other seed characteristics in bean genotypes grown in the semiarid highlands of Mexico. Between 50 and 75% of the variation in cooking time of recently harvested beans was explained by differences in the degree of water absorption after soaking for 18 h. Seed coat brightness was negatively correlated with water absorption and increased cooking time in two of the three populations evaluated. The difference in cooking time and water absorption between scarified (hilum perforated) and unscarified seed of different genotypes would indicate that the hardshell characteristic plays a major role in extending the cooking time of beans. This study indicates that when seeds have an initial moisture content of 90 g kg?1 seed or less, the hardshell problem is easily detected after soaking for 18 h, while the problem is rarely detected when initial seed moisture levels are 120 g kg?1 or higher. Selection against the hardshell characteristic could be practised in bean germplasm using this information as part of a protocol to shorten the cooking time of beans grown in the Mexican highlands.  相似文献   

8.
Multivariate procedures were used to evaluate the effect of different pre‐harvest calcium treatments on the changes of respiratory rate and ethylene production in apples both at harvest and after extended cold storage. The study was carried out over two years on ‘Golden Smoothee’ apple trees from Lleida (Spain). Trees were sprayed with a calcium chloride based formulation (STOPIT) at a concentration of 1% (v/v). The first (6 applications) and second (12 applications) treatments began 60 days after full bloom (DAFB) and were repeated at intervals of 15 and 7 days respectively. After harvesting, the fruit was stored for 4 and 6 months under controlled ultra‐low oxygen atmosphere conditions (CA‐ULO). Each time fruit was withdrawn from storage, carbon dioxide and ethylene production were measured for 14 days at 20 °C. Independently of the calcium treatments, respiration rates fell from harvesting until 6 months of storage, while ethylene production was greater on withdrawal from storage than at harvest. Respiratory rate and ethylene production correlated negatively with calcium content. However, calcium apparently had a greater effect on the respiratory capacity (CO2) of fruit than on ethylene production. Copyright © 2004 Society of Chemical Industry  相似文献   

9.
An assessment of drivers of maize storage losses was undertaken in south west Benin applying the Fractional Response Model on information collected from 400 smallholder maize farmers. The mean loss of maize during the storage period reported by farmers was estimated at 10.25 percent of the total harvest. The average marginal effect obtained from the fitted Fractional Response Model revealed that storage technologies, farmers’ post-harvest attitudes, insect damage, weather conditions and infrastructures play a significant role in storage losses maize farmers experience in south west Benin. The findings revealed that farmers who used bags and plastic containers respectively reduced storage losses by 6.7 and 7.8 percentage points compared to farmers who used woven granary baskets. The results also indicated that applying ash, neem leaves, pepper or lemon increased the storage loss by 4.11 percentage points compared to storing without protectant. Drying after harvesting decreased the storage loss by 1.9 percentage point. In contrast, the storage loss increased by 5.1 percentage points for respondents who reported insects as predators of their stored maize, and by 2.1 percentage points when it rains at the time of maize harvest. A one-degree increase in temperature was associated with an increase in storage losses of 4.4 percentage points and farmers who live at less than 26.09 km to market reduced storage losses by 0.17 percentage point. Effective policies for a sustainable reduction of storage losses among maize farmers in the area should consider the need to raise awareness about the loss issue that represents the use of woven granary basket, ash, neem leaves, pepper and lemon as storage technologies. Farmers should be informed to avoid harvesting during times of rain, encouraged to properly dry their produce after harvesting and sustainable hermetic equipment robust against insect growth during storage should be promoted.  相似文献   

10.
Postharvest storage of beans (Phaseolus vulgaris L.) can alter the color, texture, flavor and time required for cooking. These alterations have been associated with the ‘hard‐to‐cook’ phenomenon (HTC) and a reduction in the quality of the grains. HTC has been linked to the genotype, environment and/or storage conditions of the grains, but very few studies have shown the interrelationship between these factors. Therefore, the objective of this study was to analyze the effect of two genotypes, Paraiso and Peruano, grown under the same phosphorus levels, on the development of HTC. These genotypes were evaluated for phytate, protein, tannin and phosphorus contents, hydration time and cooking time when stored for 45, 90 and 135 days, at 29 °C and 5 °C at a relative humidity of 75%. HTC was observed in Peruano after 135 days, which correlated with a reduction in the phytate content. Paraiso did not show HTC even though there was a reduction of tannins during the storage period. The lower storage temperature appeared to control HTC for both genotypes. Overall, the content of phytate can be an indicative factor for the cookability of fresh beans when the relationship between genotype and storage conditions has been determined. Copyright © 2007 Society of Chemical Industry  相似文献   

11.
BACKGROUND: Low‐temperature breakdown (LTB), a disorder inducing quality loss, during and after cold storage of ‘Hayward’ kiwifruit was investigated. Harvested kiwifruits during fruit maturation or after delayed storage (DS) at 20 °C for 0, 1, 2, 3 and 4 weeks and 1 µL L?1 ethylene treatment for 24 h were stored at ? 0.5 °C for 24 weeks and additional ripening at 20 °C for 5 days. Fruit quality indices and LTB incidence and severity were determined before and after treatments. RESULTS: Harvested fruits ripened during maturation, DS and after ethylene treatment. After storage and shelf life, fruits of all treatments were at complete ripening stage. LTB incidence of early harvested fruits was high, while that of fruits of the mid (third) and late harvests was low. Fruits of the third harvest date showed progressively increased LTB incidence with increasing duration of DS to as high as 95–100% after 4 weeks. Ethylene‐treated fruits showed a comparable increase in LTB to that corresponding to 2–3 weeks of DS. CONCLUSION: In contrast to fruit maturation, postharvest (after harvest and before storage) DS at non‐chilling temperature and ethylene treatment advanced the ripening of ‘Hayward’ kiwifruit and resulted in increased LTB incidence. Copyright © 2012 Society of Chemical Industry  相似文献   

12.
‘Rojo Brillante’ persimmons were harvested in 2 different dates, early and late, and then submitted to 1‐methylcyclopropene (1‐MCP) treatment (500 nL/L) before stored at 1 or 15 °C up to 50 or 30 d, respectively. The influence of harvest date, 1‐MCP treatment, orchard, storage time, and temperature on firmness loss and color evolution during storage of ‘Rojo Brillante’ persimmon was studied. Statistical models that allowed the prediction of these 2 quality parameters during the storage, as well as the modeling of the behavior of both of them, were also evaluated. The softening, as a consequence of chilling sensitiveness when stored at 1 °C, was more accentuated in the early harvested fruit. In storage at 15 °C, also, the firmness loss was faster in fruit harvested earlier. 1‐MCP treatment drastically reduced chilling injury (CI) symptoms at 1 °C and retarded firmness loss at 15 °C, both of these effects being dependent on harvest date. The model presented to study the firmness and color relationship offers an important tool to predict firmness from fruit color measurements.  相似文献   

13.
Accumulation of Ca, Mg and K, the principal cations in dry bean (Phaseolus vulgaris L) seed, was studied under field and greenhouse conditions. ‘Cran-09’, a cranberry bean and ‘Norstar’, a navy bean, were grown to maturity under greenhouse conditions. ‘Cran-09’ had a seed weight of 605 mg, a seed Ca concentration of 1·2 g kg-1 and a Ca harvest index of 0·032. The corresponding three parameters in ‘Norstar’ were a seed weight of 161 mg, a seed Ca concentration of 2·2 g kg-1 and a Ca harvest index of 0·064. The difference in seed Ca concentration was not due to increased absorption of Ca by ‘Norstar’, but rather was due to a larger proportion of Ca in plant tops being diverted to the seed component. The larger seed Ca concentration in ‘Norstar’ was compensated to some extent by a smaller seed K concentration. In contrast to Ca, cultivar had relatively little effect on harvest indices for Mg, K, N and P. The average seed Ca concentration in six navy bean cultivars grown under field conditions was 90% more than that of three kidney and three cranberry bean cultivars. © 1997 SCI.  相似文献   

14.
Ethylene production, quality attributes and aroma compounds were analysed to determine the maturity evolution of ‘Big Top’ nectarines and ‘Royal Glory’ peaches at harvest dates ranging from 89 to 116 days after full bloom (DAFB) for nectarines and from 85 to 112 DAFB for peaches. These cultivars are highly coloured even in the early stages of maturity. However, the two cultivars had different patterns of ethylene production, this being slower in nectarines than in peaches. Principal component analysis (PCA) was used to provide partial visualisation of the complete data set in a reduced dimension plot. Separation of the two cultivars can be shown by means of a two‐dimensional plot of the samples. Although only some aroma compounds are slightly correlated with quality parameters, when aroma volatiles were included in the PCA, the aroma compound set allowed both cultivars to be classified into three stages of maturity: immature, intermediate and fully mature. Compounds such as propanol, hexyl acetate, 2‐methylpropyl acetate, limonene, butanol, (Z)‐3‐hexenyl acetate, buthyl acetate, linalool, ethanol, propyl acetate and ethyl acetate are the most important volatiles for ‘Big Top’ nectarines. It is suggested that the presence of these compounds can be used to indicate when the fruit should be harvested. The presence of γ‐decalactone, δ‐octalactone, γ‐octalactone, ethyl butyrate, hexanal and (E)‐2‐hexenol can be used to indicate the harvesting maturity stage for ‘Royal Glory’ peaches. The optimum maturity date for harvest would be 105–107 DAFB for ‘Big Top’ nectarines and 93–95 DAFB for ‘Royal Glory’ peaches. © 2002 Society of Chemical Industry  相似文献   

15.
The combination of varietal resistance with three harvest times and planting dates for efficient storage of maize against Sitophilus zeamais infestation was evaluated in the Niger Delta region of Nigeria for two seasons. Seven maize varieties made up of three susceptible local maize cultivars (Akparike, Bende and Ogbia muno) and four improved resistant varieties (ACR.97 TZL COMP.1-W, TZL COMP.4C2, ADV.NCRE-STR and BG 97 TZE COMP.3XL) were used. There were significant differences in the number of teneral adults among harvest times in all the planting dates in both years. Maize harvested when the cobs were completely dry at the latest harvest time (HVT 3) suffered significantly higher weight losses. In 2009, the highest susceptibility was apparent in a local variety Akparike planted on 17 October (PD 1) and harvested at HVT 3 by which time the cobs had completely turned yellow. Combining early planting and early harvest with resistant varieties could be an appropriate tactic for resource-poor farmers to effectively manage maize weevils in the store in the Niger Delta agro-ecological zone.  相似文献   

16.
The effect of harvest date on dry matter production per hectare and moisture content of 13 genotypes of Phalaris arundinacea (reed canary grass) was studied between 1995 and 1998 and N, P and K concentration in biomass was measured in 1998. There were two winter harvests, the first at crop senescence and the second after a subsequent delay of several weeks which varied each year. Average dry matter production was higher at the first (conventional) harvest than at the delayed harvest except in 1996. Each year there were differences in yield between genotypes and some differences were significant. Delayed harvest reduced yield by an average of 24% in 1997 and 23% in 1998 when losses resulted from 48% loss of leaf and 16% of stem matter. Delayed harvest decreased moisture content by 50% in 1997 and 52% in 1998 but it was 49% higher in 1996. In 1998, delayed harvest did not reduce N concentration in all genotypes and the reduction of P was variable, but K concentration was reduced by an average of 54%. Results indicate the suitability of reed canary grass as a biofuel, and variability between genotypes offers potential for crop improvement through selection and breeding. Copyright © 2006 Society of Chemical Industry  相似文献   

17.
Two cassava varieties, at three harvesting ages, 6, 12 and 24 months, were analyzed for sensory flavor and texture development. Maximum shear force, Texture Profile Analysis (TPA) and water absorption during cooking were determined at various sampling times. Changes during cooking were described by pseudo‐zero order models for water absorption, flavor and texture development for the fast cooking samples. The 24‐month‐old roots had higher variability and never reached optimum texture or flavor development. Significant pseudo first order models could represent hardness, cohesiveness and chewiness of the TPA, while springiness and adhesiveness varied in a non‐linear fashion. Maximum shear force was 111 N for raw samples and 8.1 N for samples that cooked in less than 25 min. Samples that required longer cook time had on the average a maximum shear force of 19 N.  相似文献   

18.
BACKGROUND: Certain apple cultivars develop a greasy feel when overripe. Treating fruits with the ripening inhibitor 1‐methylcyclopropene (1‐MCP, SmartFresh) reduces fruit greasiness. This study examines the nature of this phenomenon. ‘Royal Gala’ apples were treated with 1‐MCP at 1.0 µl L−1 following harvest. Periodically, during storage at − 1 °C for up to 6 months, fruits were evaluated for internal ethylene concentration, fruit epicuticular wax morphology (using scanning electron microscopy) and non‐polar organic solvent‐extractable (NPOSE) wax constituents of the cuticle (using gas chromatography/mass spectrometry). RESULTS: In 2004, 1‐MCP strongly inhibited internal ethylene production; however, total weight of NPOSE wax during storage was unaffected by treatment. In 2005, several wax constituents present in both ‘Autumn Gold’ and ‘Royal Gala’ showed differences during storage. In 2006, cuticular wax constituents comprising 80% of the total from ‘Royal Gala’ showed no treatment differences. Although several minor constituents did exhibit differences within treatment and sampling date, these did not appear sufficient to cause the subtle differences in surface wax morphology. CONCLUSION: 1‐MCP strongly inhibited ethylene production and delayed development of certain wax constituents thought responsible for fruit greasiness during cold storage. Subtle differences in surface wax morphology appeared unrelated to wax production. Published in 2008 by John Wiley & Sons, Ltd.  相似文献   

19.
Lower fat (10% and 14%) ground beef patties containing inner pea fiber as dry powder or as part of a high fat mixture were compared to all‐beef patties (10%, 14%, and 18% fat). Patties processed with pea fiber had improved tenderness and cooking yields and showed less change in thickness during cooking, but required longer cooking times to reach 71 °C compared to all‐beef controls. Beef flavor intensity of pea fiber patties did not differ from 10% and 14% fat all‐beef patties. Different forms of pea fiber usage produced similar patty properties. Use of inner pea fiber in lower fat beef patties improved tenderness and cooking yield, without negative effects on juiciness and flavor.  相似文献   

20.
Sweet potato breeding in the Philippines has recently integrated root quality and shelf-life attributes in varietal development. In this study, the harvest and post-harvest quality of the fleshy roots of different sweet potato genotypes were determined. These genotypes included the existing recommended varieties and the elite selections from the polycross breeding nursery and were grown during the dry and wet planting seasons. Dry matter, starch, sugar and protein contents of freshly harvested roots were found to differ widely with genotype. During storage at ambient temperatures, starch content decreased, sugar content increased and in some genotypes dry matter increased. Protein content of the stored roots varied only slightly from that of fresh roots. The different genotypes also differed in the degree of weight loss, shrivelling, decay and consequently, shelf-life. Some genotypes had short-lived roots (less than 1 month) while others had roots which were still marketable at the end of the 3-month storage period. Root quality and shelf-life similarly varied with planting season. Some genotypes had increased dry matter, starch and sugar contents and long shelf-life when planted in the dry season while others had these characteristics when produced in the wet months. Protein content generally decreased in wet-season-produced roots. However, a number of genotypes had comparable root quality and shelf-life regardless of planting season.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号