黑米皮的营养与抗氧化评价及其加工处理的保质效果

分析了黑米皮的主要营养成分、活性物质含量及总抗氧化能力，比较了热烘烤、微波加热和挤压膨化处理等加工工艺对黑米皮活性物质和总抗氧化能力的影响。结果表明，黑米皮的总黄酮、总花色苷及总抗氧化能力明显高于精米的，占黑米重12%的黑米皮的总黄酮、总花色苷和总抗氧化能力均占到整粒黑米的98%以上。黑米皮含有丰富的蛋白质、脂肪、粗纤维、维生素和矿物质等营养成分，氨基酸种类齐全，结构合理，必需氨基酸和不饱和脂肪酸比例均较高，可视为黑米营养成分和活性物质的主要载体。热烘烤、微波加热和挤压膨化3种加工方法对黑米皮总黄酮、总花色苷及总抗氧化能力的影响不尽相同，其中，挤压膨化处理的影响较小，微波处理的其次，热烘烤处理的影响较大。经挤压膨化处理后黑米皮的过氧化值和酸价变化较平缓，保质效果稳定，可作为黑米皮保藏的首选工艺。     

Sucrose synthase dominates carbohydrate metabolism and relative growth rate in growing kiwifruit (Actinidia deliciosa, cv Hayward)

Changes in fruit growth rate, carbohydrate content (glucose, fructose, sucrose and starch) and enzyme activity (sucrose synthase, UDPglucose pyrophosphorylase, fructokinase, glucokinase, sucrose phosphate synthase, ADPglucose pyrophosphorylase and invertases), in the external pericarp of kiwifruit, were measured throughout the growing season. Sucrose synthase showed the highest activity among the sucrose cleaving enzymes during large part of the growing season. The activity of invertases were much lower than that of sucrose synthase until ripening started. Sucrose synthase showed a tight although not linear relationship with the fruit RGR. Furthermore, sucrose synthase showed linear and significant correlations with the activities of both fructokinase and UDPglucose pyrophosphorylase indicating a strong co-regulation of the activities of these three enzymes involved in sucrose cleavage and sink strength, in kiwifruit. Sucrose synthase is suggested to be the dominating enzyme in the cleavage of imported carbon in kiwifruit, in tight coordination with fructokinase and UDPglucose pyrophosphorylase.     

Phenolic compounds and the antioxidant activities in litchi pericarp: Difference among cultivars

The pericarps of 10 litchi cultivars from two production seasons were studied for their phenolic concentrations and composition and activities of anti-oxidation. The total phenolic concentrations in dried litchi pericarp ranged from 51 to 102 g k g⁻¹. Different cultivars varied considerably in phenolic concentration and composition. Cultivars ‘Nuomici’ exhibited significantly higher concentrations of proanthocyanidins, flavonoids, phenolic acids and therefore total soluble phenolics than the other cultivars, while ‘Lanzhu’ and ‘Guiwei’ had minor values in phenolics. The extracts of litchi pericarp exhibited considerably high ferric reducing antioxidant power (FRAP) and strong activities of 1,1-diphenyl-2-picryhydrazyl (DPPH) scavenging, lipid peroxidation inhibiting, and oxidative DNA damage protection. The crude ethanol extracts of pericarp displayed significantly higher FRAP and stronger DPPH scavenging capacity than butylated hydroxylytoluene (BHT) and catechin. Among the tested cultivars, concentrations of major phenolics had significant linear correlations with FRAP and DPPH scavenging activities. These results indicated that litchi pericarp is rich in natural antioxidant phenolic compounds and different litchi cultivars differed considerably in phenolic concentration and antioxidant activities.     

几种处理对采后荔枝果皮水分变化与褐变的影响

研究不同处理对采后荔枝果皮水分变化及果皮褐变的影响。结果表明：HgCl2能够抑制果皮圆片失水,以0.2 mmol/L作用最显著。50 μmol/L Forskolin对果皮失水起促进作用,其它处理无显著影响。0.2 mmol/L HgCl2和果实套袋都能抑制果实失重,减缓果皮含水量下降,且能延缓果皮褐变进程。讨论HgCl2抑制果皮失水的机理。     

籽瓜皮果胶的提取工艺研究

为探究提取分离新疆籽瓜皮中果胶的最佳工艺,采用酸提醇析法探讨了原料预处理,萃取剂的种类、浓度和加入量,萃取温度、时间和浓缩比例等因素对果胶产率的影响。在此基础上,运用正交试验对萃取工艺进一步优化。确定最佳工艺条件为:籽瓜皮以细渣状沸水浴灭酶3min,萃取液为硫酸,萃取液pH值为1.5,料液比为1∶15,萃取温度为90℃,萃取次数为2,萃取时间分别为2.5h和1h,浓缩比例为1/4,冷却后经1.5倍的乙醇沉淀,果胶产率为19.5%。     

彩色小麦主要理化参数的分布分析及分层制粉技术研究

为了尽快推进彩色小麦的产业化进程,满足人们对营养型谷物的需求,实现食品营养天然、食用安全可靠。通过采用分层碾磨制粉技术和小麦抗粉碎硬度指数测定方法,研究彩色小麦的营养分布及硬度对各部分营养分离制粉的影响。结果表明,彩色小麦的氨基酸总体含量高于普通白小麦13.91%~23.32%,而其主要营养元素Se、Zn、Fe、Ca与普通白小麦比较,‘中普黑麦1号’和‘中普绿麦1号’锌、铁、钙含量比普通白小麦偏高,而‘中普紫麦1号’则普遍偏低,特别是‘中普绿麦1号’铁和钙的含量比较突出,分别高于普通白小麦的371.80%和102.86%。同时发现彩色小麦的结构营养分布等同于普通小麦,其果皮、种皮、糊粉层和胚芽具有丰富的营养。通过试验研究得出彩色小麦属营养型小麦,采用分层碾磨分离技术基本实现营养分离工业化加工的目的,同时发现影响营养分离加工的关键因素是小麦的硬度。该研究为彩色小麦营养资源的开发与合理利用提供了示范。     

酶法提取红毛丹果皮花色苷的研究

以红毛丹果皮为材料,研究酶法提取花色苷的工艺条件,结果表明,红毛丹果皮花色苷在可见光范围内的最大吸收波长为535 nm:纤维素酶适用于花色苷的提取;最佳提取条件:料液比为1 g:15 mL,采用pH 5.2的磷酸氢二钠-柠檬酸作为缓冲溶液,加酶量为混合液5％等体积的量,酶解温度55℃,酶解时间150 min.在此工艺...     

澳洲坚果果皮中主要功能性成分分析

对6个澳洲坚果品种果皮中的粗蛋白、可溶性总糖和单宁含量进行了测定和分析。结果表明,粗蛋白、可溶性总糖和单宁含量在自选品种‘南亚2号’ 的果皮内均最高,分别为9.21%、3.70%和2.16%;其次为引进品种‘O.C.’,果皮内的粗蛋白、单宁含量分别为6.42%、2.00%,自选品种‘南亚3号’ 果皮内的可溶性总糖含量为2.74%;自选品种‘南亚1号’果皮内粗蛋白含量最低,为5.04%,引进品种‘H2’果皮内的可溶性总糖和单宁含量最低,分别为0.90 %和1.06 %。     

拟茎点霉侵染对龙眼果实采后果皮褐变和活性氧代谢的影响

 【目的】研究拟茎点霉侵染对龙眼果实采后果皮褐变和活性氧代谢的影响。【方法】采后龙眼果实用拟茎点霉孢子悬浮液（浓度为104个孢子/mL）浸泡接种5 min,以无菌水处理的龙眼果实为对照。经过处理的果实在(28?1)℃、相对湿度90%下贮藏,贮藏期间定期测定果实病害指数、果皮褐变指数、MDA含量、 产生速率、活性氧清除酶（SOD、CAT、APX）活性和内源抗氧化物质（AsA、GSH）含量的变化。【结果】与对照果实相比,拟茎点霉侵染提高了龙眼果实病害指数和果皮褐变指数。同时,拟茎点霉侵染促进龙眼果皮 产生速率增加,且在整个侵染过程维持较高水平;拟茎点霉侵染0—2 d内的果皮GSH含量和APX活性明显下降而SOD和CAT活性快速上升,侵染2—5 d内的果皮APX活性快速上升而SOD和CAT活性快速下降,侵染5 d后的果皮SOD和APX活性快速下降;在整个侵染过程的果皮AsA含量快速下降,而MDA含量增加。【结论】拟茎点霉侵染导致龙眼果皮活性氧清除能力下降而积累大量活性氧,大量的活性氧对细胞膜结构的破坏会引起细胞区室化功能的丧失,使多酚氧化酶与酚类物质接触,其结果引起酚类物质的酶促氧化和黑褐色高聚物的形成而导致龙眼果皮褐变。     

超声波提取荔枝壳总黄酮的工艺研究

[目的]优化荔枝壳中总黄酮的提取工艺。[方法]采用超声波辅助法提取荔枝壳中的总黄酮,以总黄酮得率为指标,在单因素试验的基础上,采用正交设计优化提取工艺。[结果]最佳工艺工艺如下：乙醇浓度60%,超声时间30 m in,料液比1∶50,超声提取次数2次,在此工艺条件下,荔枝壳总黄酮的提取得率可达28.18 mg/g。[结论]超声波辅助法提取荔枝壳总黄酮具有方便、高效的优点,该研究为荔枝壳总黄酮的进一步开发利用奠定了试验基础。