茶多酚复合柠檬酸和氯化钙对秘鲁鱿鱼丝贮藏品质的影响

研究评价了加工工艺中0.15％茶多酚及0.05％茶多酚复合5 mmol/L柠檬酸和5 mmol/L氯化钙处理对秘鲁鱿鱼丝25℃贮藏过程中理化和感官特性的影响.结果显示,鱿鱼丝在贮藏中水分、粗蛋白、粗脂肪、pH和还原力均显著下降(P＜0.05).鱿鱼丝L*显著降低,C*明显增加(P＜0.05),表明贮藏过程中发生明显的褐变反应.鱿鱼丝中乳糖不断分解成半乳糖和葡萄糖(P＜0.05),氧化三甲胺(Trimetlyamineoxde,TMAO)降解成二甲胺(Dimethyamine,DMA)和甲醛(P＜0.05),特别是在贮藏的90 d.而茶多酚及复合柠檬酸和氯化钙处理能显著减少水分损失,抑制乳糖分解和TMAO降解,延缓脂肪氧化和TVB-N积累(P＜0.05).因此,茶多酚和柠檬酸复合添加剂对改善鱿鱼丝贮藏过程中的品质效果良好.     

茶多酚复合柠檬酸和氯化钙对秘鲁鱿鱼丝贮藏品质的影响

研究评价了加工工艺中0.15%茶多酚及0.05%茶多酚复合5 mmol/L柠檬酸和5 mmol/L氯化钙处理对秘鲁鱿鱼丝25℃贮藏过程中理化和感官特性的影响。结果显示,鱿鱼丝在贮藏中水分、粗蛋白、粗脂肪、pH和还原力均显著下降(P<0.05)。鱿鱼丝L*显著降低,C*明显增加(P<0.05),表明贮藏过程中发生明显的褐变反应。鱿鱼丝中乳糖不断分解成半乳糖和葡萄糖(P<0.05),氧化三甲胺(Trimetlyamineoxde,TMAO)降解成二甲胺(Dimethyamine,DMA)和甲醛(P<0.05),特别是在贮藏的90 d。而茶多酚及复合柠檬酸和氯化钙处理能显著减少水分损失,抑制乳糖分解和TMAO降解,延缓脂肪氧化和TVB-N积累(P<0.05)。因此,茶多酚和柠檬酸复合添加剂对改善鱿鱼丝贮藏过程中的品质效果良好。     

茶多酚对冷藏鱼糜保鲜作用的研究

为探讨茶叶提取物茶多酚在鱼产品中的保鲜作用,试验将茶多酚与其它抗氧化剂混合应用于冷藏鱼糜中,结果表明：茶多酚对冷藏鱼糜中水分含量的减少有一定的抑制作用,能延缓凝胶强度的降低,可以降低鱼糜的TVB-N值;在与其他抗氧化剂的混合应用中,Vc有增效作用,而柠檬酸效果不明显;添加茶多酚的鱼糜保鲜效果明显优于没有添加茶多酚的鱼糜。     

含茶多酚的大豆分离蛋白涂膜对甜樱桃保鲜效果的影响

将天然抑菌抗氧化物质茶多酚添加到大豆分离蛋白中制成复合涂膜液,以感官指标、硬度、腐烂指数、可溶性固形物和VC含量为质量指标定期取样分析测定,研究所制成的涂膜液在室温条件下对甜樱桃的保鲜效果。结果表明,含茶多酚的大豆分离蛋白复合涂膜液能较好地保持贮藏樱桃的感官品质,降低甜樱桃在贮藏期间的腐烂率,延缓果实硬度、VC和可溶性固形物含量的下降,从而延长果实的保鲜期。5%的大豆分离蛋白溶液中添加200mg/kg茶多酚制得的涂膜液保鲜效果显著,和对照相比,可将甜樱桃的室温保鲜期从2d延长至8d。     

茶多酚体外氧化产物颜色稳定性及对PC-3细胞生长的影响

以红茶中提取的茶黄素粗提物、绿茶多酚为对照,利用紫外扫描技术、UV-Vis法及MTT法研究了绿茶多酚纳米固定化多酚氧化酶体外氧化产物的颜色稳定性、自由基清除能力和对前列腺癌细胞PC-3生长的抑制作用。在不同pH值条件下,茶黄素粗提物和绿茶多酚纳米固定化酶体外氧化产物的紫外吸收光谱的变化趋势相似,碱性增加,吸光度增加;绿茶多酚、茶黄素粗提物及绿茶多酚纳米固定化酶体外氧化产物对DPPH·自由基均有明显清除作用,绿茶多酚纳米固定化酶体外氧化产物清除效果较绿茶多酚和茶黄素粗提物强;茶黄素粗提物及绿茶多酚纳米固定化酶体外氧化产物对PC-3细胞的生长都有抑制作用,绿茶多酚纳米固定化酶体外氧化产物优于茶黄素粗提物。因此,绿茶多酚纳米碳酸钙固定化酶体外氧化产物中茶黄素保持了红茶中茶黄素所具有的良好生物学活性。     

保鲜剂联合热处理对木薯品质及贮藏效果的影响

以华南9号木薯为试验材料,采用不同保鲜剂浸泡经热处理(60℃,5 min)后的木薯,通过测定其贮藏过程中的理化、生化指标来评价不同处理方式对木薯品质及保鲜效果的影响。结果表明:与对照相比,保鲜剂C(1.5%壳聚糖+0.15%柠檬酸+0.25%氯化钙)可显著延缓木薯块根硬度的下降,抑制色泽(L*)值的上升,延缓淀粉的降解和可溶性固形物(TSS)的增加,维持了较高水平的超氧化物歧化酶(Superoxide dismutase,SOD)活性,延缓过氧化物酶(Peroxidase,POD)活性的增加,降低了总酚含量,有效地延长了采后木薯块根的贮藏期,抑制了其品质的劣变。     

茶多酚对淡水鱼肉保鲜作用的研究

为解决鱼糜易氧化腐败的难题,将天然抗氧化剂茶多酚添加到鱼糜中并提取鱼油.通过对鱼油的酸价、过氧化值、丙二醛含量等因素变化的研究,探讨茶多酚对鱼糜的保鲜效果.结果表明:茶多酚对冷藏鱼糜具有保鲜效果,可将0.05%茶多酚定为最佳添加量.     

温度预处理对枇杷贮藏品质及活性氧代谢相关酶的影响

以“早钟六号”枇杷为试材,研究经6℃(CK)、12℃、20℃(室温)、30℃温度预处理2天后,在6℃下贮藏对采后贮藏品质及活性氧代谢相关酶的影响。结果表明：低温贮藏下,随贮藏时间的延长,过氧化物酶(POD)活性和超氧化物岐化酶(SOD)活性呈现上升趋势,过氧化氢酶(CAT)和丙二醛(MDA)含量呈现先上升后下降趋势。12℃预处理能显著延缓“早钟六号”果实可滴定酸(TA)含量和维生素C(Vc)含量的下降及果皮电导率(REC)和果实硬度的上升,但不能延缓可溶性固形物(TSS)含量的下降。12℃预处理果实最耐贮藏,在贮藏后期SOD、CAT与POD能较好地协同作用清除O2-,降低果实受自由基伤害程度,使衰老得以延缓,果实在贮藏后期仍能维持较好的风味。6℃(CK)预处理果实在贮藏后期风味劣变。20℃(室温)、30℃预处理果实后期失重、腐烂严重,不耐贮藏。     

硫营养对绿茶产量和品质的影响

研究了硫营养对绿茶产量和品质的影响及其可能的机理。试验设2个硫处理(0,50 kg S.ha-1.a-1),每个处理重复4次,完全随机区组设计。结果表明:施硫能够提高产量、增加氨基酸和抗坏血酸(AsA和DAsA)含量,降低茶多酚和酚氨比(TP/AA)。施硫对茶叶品质的改善与降低多酚氧化酶(PPO)的活性、提高硝酸还原酶(NR)和苯丙氨酸解氨酶(PAL)活性有关。     

外源抗坏血酸处理对采后菠萝黑心病发生和果实品质的影响

为了探明抗坏血酸对菠萝果实采后保鲜的有效性,本研究以“巴厘”菠萝（Ananas comosus cv. Comtede Paris） 为材料,分别用 0.2%和 0.4%（质量体积百分比 w/V）的抗坏血酸（L-Ascorbic acid,AsA）浸泡处理,以清水浸泡为 对照,0.02 mm 厚聚乙烯打孔薄膜袋包装后,于常温(25±2)℃、相对湿度 85%~95%的水果储藏库中贮藏,观察采后菠 萝黑心病发生与果实品质的变化。结果表明：AsA 处理有效地延缓菠萝黑心病的发生,保持菠萝果实的硬度,抑制可 滴定酸、可溶性固形物和维生素 C 含量的减少,在贮藏后期能够有效地抑制丙二醛（MDA）的积累。果肉氧化酶活性 测定结果表明,0.2% AsA 处理可抑制多酚氧化酶（polyphenol oxidase,PPO）活性增加,保持较高的过氧化物酶 （peroxidase,POD）活性。可见,AsA 能够有效地延缓菠萝黑心病的发生,保持采后菠萝的食用品质,抑制采后菠萝 果实酚类物质酶促氧化的发生,延缓菠萝贮藏期间的衰老进程,并且 0.2% AsA 的处理效果优于 0.4% AsA 的处理效果, 因此 0.2% AsA 为最佳处理浓度。     

茶多酚生物学活性的研究

用 ESR 法、化学发光法和分光光度法3种实验模型测定,证明茶多酚消除活性氧自由基的效率达92%—98%,明显优于维生素 C 和维生素 E。动物实验结果表明,口喂或腹腔注射给药,茶多酚能提高小白鼠的全血 GSH-Px 活力(P<0.01)和肝中 SOD 的活力(P<0.05),降低肝和血清中 LPO 的含量(P<0.01),延缓心肌 LF 的形成(P<0.01)。大白鼠在~(60)Co-γ射线照射前后口喂茶多酚,其全血中的 GSH-Px、SOD 均有提高(P<0.01),血浆和肝脏中的 LPO 含量和心肌中 LF的含量接近或优于阳性(牛磺酸)对照组。用~3H-TdR 掺入法测定茶多酚对 SR-Ⅰ癌细胞 DNA 合成的抑制率,结果达98%。荷瘤小鼠口喂茶多酚后,能明显抑制 S180或 EAC 肿瘤的增长,并能增加荷瘤小鼠的胸腺重量和胸腺细胞数,3个剂量的茶多酚胸腺指数比对照组分别提高58.5%、43.9%和34.0%。上述结果表明:茶多酚具有抗衰老、抗辐射、抗氧化、消除自由基、防治肿瘤及增加机体免疫力等多种生物学功能。     

Effects of kaolin-based particle film to control Ceratitis capitata (Diptera: Tephritidae) infestations and postharvest decay in citrus and stone fruit

Ceratitis capitata (Wiedemann) is a major pest of fruit crops due to its wide host range and distribution. The objectives of this study were to evaluate the effectiveness of Surround WP, a kaolin-based particle film, as an alternative to synthetic insecticides to control medfly infestations and postharvest decay in citrus and stone fruit. No-choice, choice and half-choice laboratory experiments with citrus fruit, nectarines and peaches showed a significant reduction of medfly punctures and landings on kaolin-treated fruit. The total loss at harvest in satsumas sprayed with Surround WP (17%) was significantly lower than in those untreated (57%) or treated with trichlorfon (68%). In 2004, the yield loss at harvest in peaches and nectarines treated with Surround WP was not different compared to fruit sprayed with fenthion and trichlorfon, while in 2005 Surround WP was significantly more effective than insecticides in reducing the incidence of damaged fruit. Citrus and stone fruit treated with Surround WP showed a lower incidence of postharvest decay than control and insecticide-treated fruit. The present study shows for the first time the lower incidence of postharvest decay in fruit protected with Surround WP, which represents a suitable alternative to conventional insecticides in integrated and traditionally managed orchards.     

茶多酚-壳聚糖复合膜的制备及保鲜效果研究

本研究以聚乙烯醇（PVA）和壳聚糖（CTS）为基材,甘油作为增塑剂,以茶多酚（TP）为功能性添加剂制备无污染、可降解且具有抗氧化功能的活性包装材料TP-CTS/PVA复合膜,分析TP浓度对复合膜机械性能、抗氧化能力、抑菌能力等理化性质的影响,研究复合膜与包装相关性能的影响,以期提高复合膜的综合性能。将其应用于圣女果的保鲜,测定其在贮存期间理化指标及微生物指标,进一步将不同TP浓度的复合膜涂抹于新鲜圣女果表面,分析圣女果在贮存期间的感官品质、腐烂率、失重率、可溶性糖、可滴定酸等指标的变化,系统研究复合膜对圣女果的保鲜效果。结果表明：以TP为功能性添加剂共混CTS和PVA制备的复合膜兼具抗氧化和抑菌效果;随着TP浓度增加,复合膜的颜色逐渐变深,TP浓度为1.5%时,复合膜的水溶性最低(19.85±0.64)%,此时复合膜的抗张强度呈最大值(13.19±0.77)MPa;当TP浓度增大,其对Escherichia coli和Staphylococcus aureus的抑菌能力也不断增强,能有效抑制细菌生长; TP浓度为2.0%时,复合膜对DPPH自由基清除率达到最大值(38.53±0.91)%;采用复合膜涂覆对圣女果能减少水分蒸腾、延缓果蔬机体衰老从而起到良好的保鲜效果,涂膜能有效延缓圣女果的腐烂和失水变质的现象,表明TP-CTS/PVA复合膜能改善果蔬的保鲜货架期和商品价值;在相同贮存时间内,当用TP浓度为1.50%复合膜涂抹圣女果时,圣女果的感官评价得分、失重率、腐烂率、可滴定酸含量、可溶性糖含量等各项指标较其他TP浓度试验组效果更好。研究表明,当TP浓度为1.5%~2.0%时制备的TP-CTS/PVA复合膜其抑菌性、耐水性、抗氧化性、以及保鲜性能等各项指标较为均衡,将其实际应用于生产中可根据需求调整TP浓度。本研究目的为探索开发抗菌抗氧化功能型复合膜和功能型包装材料替代塑料包装材料的可能性,为同时解决食品保鲜与环境污染问题提供依据。     

茶多酚对小鼠辐射损伤的防护效应

用ＮＩＨ小鼠作动物整体试验,测定茶多酚（ＴＰ）对６０Ｃｏ－γ射线辐照损伤的防护和治疗效应。实验共分５组,即正常对照组、６０Ｃｏ－γ辐照组、辐照前给ＴＰ组、辐照后给ＴＰ组、阳性药对照组。其中给药组分别以１／５ＬＤ５０和１／１０ＬＤ５０二个剂量的ＴＰ水溶液灌胃（ｉｇ）、阳性药组用生白宝ｉｇ,其他各组ｉｇ生理盐水。６０Ｃｏ－γ射线照射总剂量为４．５Ｇｙ,剂量率为０．９８Ｇｙ／ｍｉｎ,辐照后第１０天观察各组小鼠的死亡率、体重、血象、白细胞分类计数、脾指数、胸腺指数、ＣＦＵ－Ｓ、网织红细胞数、骨髓有核细胞数、粒细胞有丝分裂指数和ＰＣＥ的微核细胞率等。结果表明：辐照前给ＴＰ组小鼠的血像、免疫器官指数、ＣＦＵ－Ｓ及粒细胞ＭＩ等明显高于６０Ｃｏ－γ辐照组,并能抑制骨髓ＰＣＥ的ＭＮＣＦ;在辐照后给ＴＰ组中测得的造血及免疫系统的有关数据与６０Ｃｏ－γ组比较也明显提高,说明ＴＰ对机体造血和免疫系统受到电离辐射损伤时不仅具有明显的防护效应,而且对辐射损伤具有一定的修复治疗作用。     

含硒植物营养剂对桃和梨吸收铅、镉、汞的拮抗作用

采用田间试验,研究含硒植物营养剂对水蜜桃和沙梨果实中有益矿物质元素硒和重金属元素铅、镉、汞的影响。结果表明,植物营养剂处理水蜜桃果实中有益矿物质元素硒含量比对照增加1 132.7%,重金属元素铅、镉、汞含量比对照分别减少了83.5%,65.5%,23.9%;植物营养剂处理沙梨果实中有益矿物质元素硒含量比对照增加了1 542.9%,重金属元素铅、镉、汞含量比对照分别减少了30.0%,23.9%,6.3%。     

Fumigation of stonefruit with acetic acid to control postharvest decay

Acetic acid was an effective postharvest fumigant to destroy fungal spores on peaches, nectarines, apricots, and cherries. Decay by Monilinia fructicola and Rhizopus stolonifer on Harbrite peaches was prevented by as little as 1.4 or 2.7 mg l⁻¹ acetic acid, respectively. Harbrite peaches fumigated with 2.7 mg l⁻¹ acetic acid were slightly injured, the phytotoxicity indicated by light brown streaks. Higher concentrations of acetic acid increased injury; the streaks darkened and became much more pronounced. Glohaven peaches treated in the orchard with captan at 5% bloom, full bloom, ripening fruit, and 2 days before harvest then fumigated with 2.7 mg l⁻¹ acetic acid after harvest had significantly less postharvest brown rot (12.5%) than fruit treated with captan alone (25.0%). Decay of Lambert cherries, primarily due to Alternaria spp., was reduced from 38.9 to 10.0% by fumigation with 2.7 mg l⁻¹ acetic acid. Unfortunately, small pits developed in the fruit surface during storage at 1 °C. Brown rot (M. fructicola) of Tilton apricots was reduced from 100 to 25% by fumigation with 2.0 mg l⁻¹ acetic acid without signs of severe phytotoxicity.     

Injury to apples and peaches at harvest from feeding by Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) nymphs early and late in the season

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is an invasive species that has become an important orchard pest in the Mid-Atlantic region of the US. Adults and nymphs feed on tree fruit. Feeding injury from adults has been characterized but the injury from nymphs has not been examined systematically. Since the four plant-feeding instars of H. halys (second through fifth) differ substantially in size, it is plausible that the effects of their feeding on fruit injury and injury expression may differ among them. We compared feeding injury at harvest from young nymphs (second plus third instars), older nymphs (fourth plus fifth instars), and adults that were caged on ‘Smoothee Golden’ apples and ‘Redhaven’ peaches in early June (peach and apple), late July (peach), and late August (apple). Individual apples and peaches were caged at fruit set and assigned to the following treatments (n = 28/treatment): 1) control (no H. halys), 2) young nymphs or 3) adults early in the season, and 4) young nymphs, 5) older nymphs or 6) adults later in the season. Fruit in each treatment were exposed to 3–4 young nymphs, two older nymphs or 1–2 adults placed in the cages for 96 h and evaluated for external and internal feeding injury within 36 h after harvest. No injury was recorded from unexposed peaches or apples. The percentage of injured fruit and number of injuries per fruit varied significantly among the exposed treatments. Early season feeding by young nymphs yielded the least injury to peaches and apples. In apples, the highest percentage of injured fruit and number of injuries per fruit were caused by late season feeding by adults. In peaches, early season adult feeding produced the highest percentage of injured fruit and injuries per fruit. More internal than external injury was recorded on peach and no such difference was observed on apple. The implications of these findings on H. halys management in fruit orchards are discussed.     

Economic implications of a virus prevention program in deciduous tree fruits in the US

Viral diseases in fruit trees present a potential danger that could injure the fruit industry, the planting stock industry (nurseries), and consumers in the United States and abroad. Currently, the US has a virus protection program (VPP) that serves to minimize the spread of viral diseases. This paper reports research estimating the economic consequences of the loss of the program on nurseries, growers and consumers. The potential economic losses are a measure of the value of the existing program. The paper focuses on apples, sweet cherries, and Clingstone peaches.

The effects of a loss of a VPP on nurseries would include direct and indirect losses from viral diseases in the form of lower quantity and quality of planting stocks. Fruit growers would be affected by reduced plant growth and fruit yield. Consumers would be affected by higher prices and reduced quantity of fruit.

We measured benefits of the virus prevention program as changes in consumer and producer surpluses. Empirical estimates were made using the method of avoided losses. Benefit estimates to three economic sectors—nurseries (avoided change in producer surplus), producers (avoided change in consumer and producer surpluses), and consumers (avoided change in consumer surplus)—were calculated. Total benefits for all three sectors were approximately $227.4 million a year, or more than 420 times the cost of the program. Our analysis utilizes a method that might be used to evaluate other programs that prevent the introduction of plant diseases.     

Investigations on the Wound Healing Potential of Tilapia Piscidin (TP)2-5 and TP2-6

Wound healing is a highly orchestrated process involving many cell types, such as keratinocytes, fibroblasts and endothelial cells. This study aimed to evaluate the potential application of synthetic peptides derived from tilapia piscidin (TP)2, TP2-5 and TP2-6 in skin wound healing. The treatment of HaCaT keratinocytes with TP2-5 and TP2-6 did not cause cytotoxicity, but did enhance cell proliferation and migration, which could be attributed to the activation of epidermal growth factor receptor signaling. In CCD-966SK fibroblasts, although TP2-5 (31.25 μg/mL) and TP2-6 (125 μg/mL) showed cytotoxic effects, we observed the significant promotion of cell proliferation and migration at low concentrations. In addition, collagen I, collagen III, and keratinocyte growth factor were upregulated by the peptides. We further found that TP2-5 and TP2-6 showed pro-angiogenic properties, including the enhancement of human umbilical vein endothelial cell (HUVEC) migration and the promotion of neovascularization. In a murine model, wounds treated topically with TP2-5 and TP2-6 were reduced by day 2 post-injury and healed significantly faster than untreated wounds. Taken together, these findings demonstrate that both TP2-5 and TP2-6 have multifaceted effects when used as topical agents for accelerating wound healing.     

Suppressing Mediterranean fruit fly (Diptera: Tephritidae) with an attract-and-kill device in pome and stone fruit orchards in Western Australia

Attract-and-kill is a possible alternative to the conventional control of Mediterranean fruit fly (medfly), Ceratitis capitata Wiedemann (Diptera: Tephritidae) with bait or cover sprays of organophosphate insecticides. In this study, we determined if an attract-and-kill device (MagMED^®) could be applied alone at the recommended rate (80 devices/ha), or needed to be combined with other conventional control tactics to suppress medfly in deciduous fruit orchards (apple, nectarine, peach, pear, plum). We also determined if attract-and-kill had any detrimental effects on naturally occurring beneficial insects. Based on an acceptable level of crop loss of 2–5% (the level of crop loss growers can tolerate), attract-and-kill suppressed medfly and reduced crop loss below the acceptable level in orchards with additional controls. Attract-and-kill was most effective when combined with either bait spraying, cover spraying or both. Combining attract-and-kill with cover sprays of fenthion resulted in a drop in crop loss of apples from 2.5% to 0.5%. By combining attract-and-kill with weekly bait sprays and two cover spray applications, crop loss fell from 13.7% to 4.3% in peaches, from 6.3% to 5% in nectarines and from 6.3% to 3.7% in pears. Twice weekly bait spraying was the most effective technique at suppressing medfly, providing acceptable control when applied alone, which further improved by combining with attract-and-kill. By combining attract-and-kill with twice weekly bait spraying crop loss fell from 2% to 1% in nectarines and from 4% to 2% in apples. In laboratory trials, attract-and-kill devices killed 100% of brown lacewings (Micromus tasmaniae Walker) and 94% of transverse ladybeetles (Coccinella transversalis Fabricius) 24 h after contact. However, orchard samples suggest that it may not pose any significant negative impact on naturally occurring beneficials such as Neuroptera, Hymenoptera, Coleoptera, Thysanoptera and Syrphidae in the field.