预处理对红枣分段间歇微波耦合热风干燥特性及品质的影响

为探究分段间歇微波耦合热风干燥红枣最佳工艺,分析不同预处理对红枣品质的影响。该文采用响应面法,优化出最佳干燥工艺为:第一段间歇比为4、水分转换点为1g/g、第二段间歇比为6。此条件下,干燥时间为625.27 min,能耗为5 128 kJ,维生素C质量分数为419 mg/(100g),经验证,模型预测误差小于5%。基于最佳工艺,探究热烫、油酸乙酯结合预冻和高压二氧化碳3种预处理方式对红枣干燥速率、单位耗能及品质的影响。结果显示,油酸乙酯结合预冻处理组干燥时间最短(P0.05)、能耗最低(P0.05);高压二氧化碳处理组干燥后维生素C、总酮、总酚质量分数,抗氧化能力均最高(P0.05);热烫预处理组褐变程度最低(P0.05),组间色泽无明显差异(P0.05)。试验证实,高压二氧化碳联合分段间歇微波耦合热风干燥是一种高效干燥技术,能保证红枣的营养品质,研究为该项技术的推广提供基础数据。     

不同施肥条件对谷子β-胡萝卜素和叶黄素含量的影响

为了探究不同施肥条件对谷子类胡萝卜素含量的影响及筛选谷子高类胡萝卜素含量的施肥种植条件,运用L16(45)正交试验,以16种不同氮、磷、钾施肥配比作为长农35号谷子的施肥种植条件,测定各施肥条件下谷子β-胡萝卜素和叶黄素含量,并对其进行分析。结果表明,不同施肥条件对谷子β-胡萝卜素和叶黄素含量均有显著影响,最佳施肥条件为尿素485 g、重过磷酸钙0 g、硫酸钾300 g,此条件下谷子的β-胡萝卜素和叶黄素总含量最高。通过方差分析和偏相关分析得到氮、磷、钾肥对谷子β-胡萝卜素和叶黄素含量的影响大小依次为氮肥钾肥磷肥。本研究为培育高类胡萝卜素含量谷子所需的施肥条件提供了理论依据和现实基础。     

马铃薯生全粉中不饱和脂肪酸微波萃取工艺参数优化及应用

为了优化马铃薯生全粉不饱和脂肪酸的微波萃取工艺,该试验采用软件Design-Expert 8.05分析以及响应面法来优化马铃薯生全粉中不饱和脂肪酸微波萃取工艺,得出马铃薯生全粉中不饱和脂肪酸的萃取模型P=0.000 10.01,R2=0.939 8,并确定马铃薯生全粉中不饱和脂肪酸最佳萃取工艺:萃取温度81℃,萃取时间11 min,萃取溶剂中丙酮占比0.802 5,料液比3.25∶1,各因素对不饱和脂肪酸质量分数影响大小分别为:丙酮占比料液比萃取温度萃取时间,实测不饱和脂肪酸质量分数为1.081 mg/g和拟合方程的预测值1.084 mg/g基本一致。将该优化方案应用于热风干燥温度对马铃薯生全粉中不饱和脂肪酸含量影响的分析中,结果表明:随着干燥温度的升高,亚油酸质量分数显著增加(P0.05),总不饱和脂肪酸质量分数增加(P0.05)。优化试验为热风干燥条件对马铃薯品质影响的研究提供了理论依据。     

杀菌方式对即食胡萝卜片挥发性风味物质的影响

为研究不同杀菌方式对即食胡萝卜片挥发性风味物质的影响,运用固相微萃取和气相色谱-质谱联用技术,分别对新鲜胡萝卜片和经巴氏杀菌、超高压杀菌、热辅助超高压杀菌处理的即食胡萝卜片及其贮藏期间(4℃,60 d)的挥发性组分进行对比分析。试验结果表明:新鲜胡萝卜片的主要芳香成分为萜烯类物质。与未杀菌组相比,经不同杀菌处理后,即食胡萝卜片的萜烯类物质含量均有所降低,其中巴氏杀菌组降低的最多。在贮藏前期(20~30 d),超高压处理即食胡萝卜片的萜烯类物质的含量最高,超高压杀菌在短期内较好地保持了胡萝卜特有的香气,即食胡萝卜片品质较好;其次是热辅助压力杀菌组,热辅助压力杀菌组即食胡萝卜片的β-蒎烯、β-石竹烯的含量较其他处理组较高,较好地保持了胡萝卜的松树树脂香气以及辛香气味;而巴氏杀菌组即食胡萝卜片的萜烯类物质含量最低,即食胡萝卜片的品质相对较差。研究结果可为新型杀菌技术在即食产品领域的应用提供参考。     

盐腌对浙东白鹅肉品质及结构的影响

为探究盐腌对浙东白鹅肉的品质及结构的影响,研究了经不同食盐质量分数(4%、6%、8%、10%、12%)腌制后的白鹅胸肉的理化品质、质构特性以及微观结构的变化,并运用拉曼光谱技术分析了盐腌对蛋白质结构的影响。结果表明,随着盐腌食盐质量分数的增大,蛋白水解指数降低,氨基酸总量增加,肌节长度变小,鹅肉的硬度增大。拉曼光谱分析显示,蛋白质的二级结构中α-螺旋含量由49.74%下降为41.24%,β-折叠的含量由18.01%增加到26.44%。相关性分析表明,α-螺旋与食盐质量分数、水分含量以及硬度负相关,β-折叠与食盐用量、水分含量以及硬度正相关。本研究结果为盐腌鹅肉制品提供了一定的理论依据。     

甘薯全粉加工中无硫复合护色工艺优化

为了优化甘薯全粉无硫复合护色工艺,该文通过考察柠檬酸、柠檬酸亚锡二钠、植酸、亚硫酸氢钠和抗坏血酸5种护色剂对甘薯全粉色泽的影响,优选出柠檬酸和抗坏血酸作为甘薯全粉加工合适的护色剂;通过正交试验,得到柠檬酸-抗坏血酸无硫复合护色剂的最佳护色工艺为:将10 mm厚的甘薯切片在质量分数为0.3%的柠檬酸和0.1%抗坏血酸的复合护色液中护色处理30 min,可使制得的甘薯全粉亮度值L*达90.58,多酚氧化酶的抑制率达88.13%.研究发现柠檬酸的添加能显著提高抗坏血酸的热稳定性;酶促褐变产物紫外-可见光谱扫描显示,加入复合护色剂后410 nm处吸收峰明显减弱,表明复合护色剂能有效抑制酶促褐变反应的发生;圆二色谱研究表明多酚氧化酶经复合护色剂处理后,酶蛋白二级结构中α-螺旋减少,而β-折叠结构增多,酶蛋白的分子构象被改变,从而降低多酚氧化酶活力.该文为甘薯全粉加工中的无硫复合护色工艺提供了参考.     

硒对胡萝卜含硒量、产量及品质的影响

采用不同浓度Na2SeO3进行胡萝卜叶面喷施的田间试验,研究胡萝卜对硒的吸收、转化特点和硒对胡萝卜产量、品质等的影响。结果表明,叶面施硒可明显提高胡萝卜中各形态硒含量,随施硒量的增加,有机硒转化率上升;其总硒、有机硒含量在最大处理浓度(500.mg/kg)呈最高,分别是CK的15.9和26.6倍。施硒胡萝卜产量较对照降低,但未达显著水平。营养品质中除Vc下降,P变化不一外,总糖、胡萝卜素、粗纤维、Ca、Mg、Fe、K在一定浓度下有不同程度提高。综合分析硒对胡萝卜含硒量、产量、各品质因素以及对人、畜食用的安全性,施硒量以不超过1.0mg/kg为宜。     

RS基因转化胡萝卜及高白藜芦醇转基因胡萝卜株系筛选

摘要：白藜芦醇是具有抗病及多种保健功能的芪类次生代谢物,胡萝卜则是富含β胡萝卜素等多种营养成分的重要蔬菜。本研究着眼于创建具有白藜芦醇保健功能的胡萝卜新种质资源，在对葡萄白藜芦醇合成酶（Resveratrol synthase 简称RS）基因针对在胡萝卜中表达的密码子优化基础上构建无潮霉素抗性基因的转化载体pCB－RS－hyg-，应用农杆菌介导遗传转化方法将pCB和pCB－RS－hyg-共转化到胡萝卜并获得再生植株。经过T0、T1和T2代的逐代筛选，获得2个白藜芦醇含量较高的转基因胡萝卜株系，为进一步开发利用以及相关代谢途径的分子生物学研究奠定了重要基础。     

贮藏温度对冷破碎番茄浆品质变化的影响

为探讨冷破碎番茄浆在贮藏过程中的品质变化,以指导冷破碎番茄浆的贮藏,该文研究了其在0、25和37℃条件下贮藏150 d的品质变化,并对产品中主要指标的变化进行了动力学分析。25和37℃贮藏条件下冷破碎番茄浆中氨基酸、总糖、蔗糖、果糖、维生素C含量和颜色指标（亮度L*、红值a*和黄值b*）均显著下降,而5-羟甲基糠醛（HMF）含量、褐变度（BD）和总色差ΔE显著增加,其中总氨基酸、总糖、维生素C、HMF和BD的变化均符合一级动力学模型;而且HMF含量与BD变化呈线性关系,符合零级动力学模型。但是番茄红素和可溶性固形物含量变化不显著,而酸度随温度和时间的增加呈增加趋势。0℃贮藏条件下,除维生素C含量显著下降外,上述其他指标均无显著变化。表明高温贮藏显著降低冷破碎番茄浆的品质,而低温贮藏可有效保护冷破碎番茄浆的品质。     

α-乳白蛋白提高β-胡萝卜素乳液稳定性

为了提高β-胡萝卜素乳液稳定性,该研究利用α-乳白蛋白(α-LA)为乳化剂,考察了不同α-LA添加量(0.25%~3.00%)对10%的水包油(O/W)β-胡萝卜素乳液粒径、电位、快速稳定性、包埋率、界面α-LA含量和化学稳定性的影响。结果表明:随着α-LA添加量的增加,β-胡萝卜素乳液粒径减小,电位增加,包埋率提高;当α-LA添加量大于1.50%时,乳液粒径、电位和包埋率不再随着α-LA添加量的增加而变化(P0.05)。乳液的Turbiscan扫描指数(TSI)在α-LA添加量大于1.50%之后没有显著性变化,β-胡萝卜素乳液趋于稳定。随着α-LA添加量的增加,水油界面上α-LA含量显著增加(P0.05)。当α-LA添加量大于1.00%时,β-胡萝卜素在乳液中的保留率不再随着α-LA添加量的增加而增加。研究结果表明α-LA是一种可以应用在β-胡萝卜素乳液中的乳化剂,在α-LA添加量为1.50%时,可以得到物理和化学稳定性较好的β-胡萝卜素乳液,为食品工业中应用β-胡萝卜素提供了参考。     

Determination of carotenoids, total phenolic content, and antioxidant activity of Arazá (Eugenia stipitata McVaugh), an Amazonian fruit

The fruit of Arazá (Eugenia stipitata McVaugh) native to the Colombian Amazon is considered a potentially economically valuable fruit for the Andean economy due to its novel and unique taste. The fruit has an intense yellow color, but its chemical composition and properties have not been well studied. Here we report the identification and quantitation of carotenoids in the ripe fruit using high performance liquid chromatography (HPLC) with photodiode array detector (PDA) and atmospheric pressure chemical ionization (APcI) mass spectrometry (MS/MS). The qualitative carotenoid profile of the fruit according to maturity stage was also observed. Furthermore, antioxidant activity of the peel and pulp were assessed using the ferric reducing ability of plasma (FRAP), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods, in addition to chemical indexes and total phenolic content. Multiple carotenoids were identified in the peel and pulp including four xanthophylls (free and esterified as their mono and diesters) and two carotenes. One of the xanthophylls was tentatively identified as zeinoxanthin, while the others were identified as lutein, zeaxanthin, and β-cryptoxanthin. Carotenes included α-carotene and β-carotene. The total carotenoid content was significantly higher in the peel (2484 ± 421 μg/100 g FW) than in the pulp (806 ± 348 μg/100 g FW) with lutein, β-cryptoxanthin, and zeinoxanthin as the major carotenoid components. The unique carotenoid composition of this fruit can differentiate it from other carotenoid-rich fruits and perhaps be useful in authentication procedures. Overall, results from this study suggest that Colombian Arazá may be a good edible source of carotenoids important in retinal health as well as carotenoids with provitamin A activity. Therefore, Arazá fruit can be used as a nutraceutical ingredient and in production of functional foods in the Colombian diet.     

Carotene and novel apocarotenoid concentrations in orange-fleshed Cucumis melo melons: determinations of β-carotene bioaccessibility and bioavailability

Muskmelons, both cantaloupe (Cucumis melo Reticulatus Group) and orange-fleshed honeydew (C. melo Inodorus Group), a cross between orange-fleshed cantaloupe and green-fleshed honeydew, are excellent sources of β-carotene. Although β-carotene from melon is an important dietary antioxidant and precursor of vitamin A, its bioaccessibility/bioavailability is unknown. We compared β-carotene concentrations from previously frozen orange-fleshed honeydew and cantaloupe melons grown under the same glasshouse conditions, and from freshly harvested field-grown, orange-fleshed honeydew melon to determine β-carotene bioaccessibility/bioavailability, concentrations of novel β-apocarotenals, and chromoplast structure of orange-fleshed honeydew melon. β-Carotene and β-apocarotenal concentrations were determined by HPLC and/or HPLC-MS, β-carotene bioaccessibility/bioavailability was determined by in vitro digestion and Caco-2 cell uptake, and chromoplast structure was determined by electron microscopy. The average β-carotene concentrations (μg/g dry weight) for the orange-fleshed honeydew and cantaloupe were 242.8 and 176.3 respectively. The average dry weights per gram of wet weight of orange-fleshed honeydew and cantaloupe were 0.094 g and 0.071 g, respectively. The bioaccessibility of field-grown orange-fleshed honeydew melons was determined to be 3.2 ± 0.3%, bioavailability in Caco-2 cells was about 11%, and chromoplast structure from orange-fleshed honeydew melons was globular (as opposed to crystalline) in nature. We detected β-apo-8'-, β-apo-10', β-apo-12'-, and β-apo-14'-carotenals and β-apo-13-carotenone in orange-fleshed melons (at a level of 1-2% of total β-carotene). Orange-fleshed honeydew melon fruit had higher amounts of β-carotene than cantaloupe. The bioaccessibility/bioavailability of β-carotene from orange-fleshed melons was comparable to that from carrot (Daucus carota).     

Quince (Cydonia oblonga Miller) fruit (pulp, peel, and seed) and Jam: antioxidant activity

To study the antioxidant activity of quince fruit (pulp, peel, and seed) and jam, methanolic extracts were prepared. Each extract was fractionated into a phenolic fraction and an organic acid fraction and was analyzed by high-performance liquid chromatography (HPLC)/diode array detection and HPLC/UV, respectively. Antiradical activities of the extracts and fractions were evaluated by a microassay using 1,1'-diphenyl-2-picrylhydrazyl. The phenolic fraction always exhibited a stronger antioxidant activity than the whole methanolic extract. Organic acid extracts were always the weakest in terms of antiradical activity, which seems to indicate that the phenolic fraction gives a higher contribution for the antioxidant potential of quince fruit and jam. The evaluation of the antioxidant activity of methanolic extracts showed that peel extract was the one presenting the highest antioxidant capacity. The IC50 values of quince pulp, peel, and jam extracts were correlated with the caffeoylquinic acids total content. Among the phenolic fractions, the seed extract was the one that exhibited the strongest antioxidant activity. The IC50 values of quince pulp, peel, and jam phenolic extracts were strongly correlated with caffeoylquinic acids and phenolics total contents. For organic acid fractions, the peel extract was the one that had the strongest antiradical activity. The IC50 values of quince pulp, peel, and jam organic acid fractions were correlated with the ascorbic acid and citric acid contents.     

Particle size reduction leading to cell wall rupture is more important for the β-carotene bioaccessibility of raw compared to thermally processed carrots

The amount of nutrients that can be released from food products (i.e., nutrient in vitro bioaccessibility) is often studied as it is a starting point for investigating nutrient bioavailability, an indicator for the nutritional value of food products. However, the importance of mastication as a particle size reduction technique is poorly understood and is often neglected during in vitro procedures determining bioaccessibility. Therefore, the aim of the present work was to study the effect of mechanical breakdown on the β-carotene bioaccessibility of carrot samples, having different textural/structural characteristics (as a result of thermal processing). In the first part of this study, the all-E-β-carotene bioaccessibility of carrot particles of different sizes (ranging from cell fragments up to large cell clusters), generated from raw as well as from gently and intensely cooked carrot samples, was determined. In the second part of the study, the effect of human mastication on the particle size reduction of raw as well as of gently and intensely cooked carrot samples was investigated in order to allow identification and validation of a technique that could mimic mastication during in vitro procedures. Results showed a strong dependency of the all-E-β-carotene bioaccessibility on the particle size for raw and gently cooked carrots. After intense cooking, on the other hand, a considerable amount of all-E-β-carotene could be released from cell fragments (smaller than a cell) as well as from small and large cell clusters. Hence, the importance of mechanical breakdown, and thus also of (in vitro) mastication, is dependent on the carrot sample that is considered (i.e., the extent to which the carrot sample has been thermally processed prior to the particle size reduction). Structural changes occurring during mechanical and thermal processing are hereby key factors determining the all-E-β-carotene bioaccessibility. The average particle size distribution curves of raw and cooked carrots, which were chewed by 15 persons, could be mimicked by mixing 50 g of carrots using a Grindomix (Retsch) at 2500 rpm during 5 s. Based on this scientific knowledge, the identified in vitro mastication technique was successfully integrated in the in vitro digestion procedure determining the all-E-β-carotene bioaccessibility of carrot samples.     

黄花菜多酚类化合物的鉴定及漂烫与贮藏对其稳定性的影响研究

为鉴定黄花菜多酚类化合物的结构并研究漂烫与贮藏对其稳定性的影响,本研究采用响应面和正交试验设计,四极杆飞行时间液质串联系统,以及三重四极杆液质串联系统,研究了超声波辅助提取黄花菜多酚,HPD-600大孔树脂吸附多酚,乙醇解吸附多酚的最佳条件,对多酚类化合物进行分离纯化和结构鉴定,并对新鲜、漂烫与室温贮藏的黄花菜多酚类化合物含量进行分析。结果表明,超声辅助提取黄花菜多酚类化合物的最佳条件为:乙醇浓度66%,时间22 min,温度43℃,料液比1∶12 g·mL^-1, 此条件下多酚得率为2.12%;HPD-600大孔树脂吸附多酚的最佳条件为温度50℃,pH值6,吸附时间3 h,此条件下多酚吸附率为28.76%;无水乙醇解吸附的最佳条件为温度60℃,pH值6,解吸时间3 h,此条件下多酚解吸率为78.94%,纯化的多酚溶液浓度为0.61%;黄花菜多酚类化合物的含量由高到低依次为芦丁、绿原酸和槲皮素,高温漂烫和贮藏极易引起多酚类化合物的损失,导致加工后黄花菜的营养品质下降。本研究结果可为黄花菜多酚类化合物的分离鉴定及漂烫和室温贮藏对其稳定性影响的研究提供参考。     

提高罐藏蘑菇的得率的研究

为了探讨提高罐藏蘑菇得率的更好方法，用正交试验设计方法进一步分析浸泡-冷藏-浸泡处理与浸泡-冷藏-真空水合处理方法中各因素以及蘑菇的预煮时间、预煮液中的柠檬酸浓度对罐藏蘑菇的得率的影响。试验结果表明，在浸泡-冷藏-浸泡处理与浸泡-冷藏-真空水合处理方法中，只有冷藏处理显著影响罐藏蘑菇的得率。蘑菇的预煮时间与预煮液中的柠檬酸浓度对罐藏蘑菇的得率也有较显著的影响。将蘑菇在2℃的条件下作20～24 h的冷藏处理后再预煮，并适当延长预煮时间可提高罐藏蘑菇的得率。     

壳寡糖和油菜素甾醇处理对番茄产量和品质的影响

为了探究壳寡糖与油菜素甾醇处理对番茄(Solanum lycopersicum L.)果实产量、感官品质、营养品质和风味品质的影响,本试验设置4个处理：对照组(CK)、壳寡糖处理组(0.5 g·L^-1COS)、油菜素甾醇处理组(0.5 g·L^-1BR)、复合处理组(0.5 g·L^-1COS+0.5 g·L^-1BR),对开花结果期的番茄植株进行叶面喷施。结果表明,壳寡糖与油菜素甾醇复合处理可以显著提高番茄产量;促进果实着色和软化;协同促进番茄中番茄红素、总胡萝卜素和维生素C的积累,相比CK分别提高88.3%、76.3%和28.6%。此外,二者复合处理可有效提高番茄中可溶性糖(葡萄糖和果糖)的含量,并降低有机酸(苹果酸和柠檬酸)的水平,从而提高番茄糖酸比。本研究结果为设施栽培下番茄产量和品质的提升提供了理论依据。     

Carotenoid content, physicochemical, and sensory qualities of deep-fried carrot chips as affected by dehydration/rehydration, antioxidant, and fermentation.

Carrot slices were subjected to one of the following experiments prior to deep-frying: (A) dehydration/rehydration, (B) soaking in different antioxidants, and (C) fermentation with/without blanching. There were no significant differences (P > or = 0.05) in carotenoid contents among carrot chips treated with/without dehydration. Soaking in sodium metabisulfite resulted in the highest carotenoid content and lightness (L), redness (a), and yellowness (b) values among the antioxidant treatments. Fermentation without blanching significantly decreased (P < 0.05) carotenoid content, vitamin A activity, and fat content. Dehydration and fermentation with blanching significantly increased (P < 0.05) the lightness (L), redness (a), and yellowness (b) values of the chips. Dehydration/rehydration, but not antioxidant and fermentation, significantly decreased (P < 0.05) the water activity of the chips. The textural values of carrot chips prepared using sodium metabisulfite, without dehydration and without fermentation, were the lowest among other treatments which suggests the crispiest. Carrot chips prepared using sodium metabisulfite, without dehydration and without fermentation, had the highest carotenoid content and retention, and the highest overall acceptability score.     

苦杏仁去皮热风干燥适宜温度提高油脂品质

为探索适宜的杏仁热风干燥温度,以热烫去皮处理后的湿杏仁为试验材料,研究了热风干燥不同温度对杏仁及其油脂的感官、理化和营养品质的影响。结果表明,经热烫去皮、干燥处理后可以得到颜色较浅的杏仁油,有利于提高杏仁油的感官品质,但会造成杏仁油过氧化值显著升高(P0.05),油酸、亚油酸、十七碳烯酸、二十碳一烯酸等不饱和脂肪酸的比例和甾醇含量降低,棕榈酸、棕榈油酸、硬脂酸、十七碳烷酸、二十碳烷酸、二十碳一烯酸的比例和总生育酚含量升高,对杏仁油的理化特性和营养品质产生影响。但不同脂肪酸及其伴随物种类、不同温度处理变化幅度不同。随着干燥温度的提高,干燥速率逐渐加快,杏仁及杏仁油的颜色逐渐加深,杏仁油亮度下降,酸价略有升高,但不同干燥温度之间差异不显著(P0.05);过氧化值呈上升趋势,且80℃以上干燥处理显著高于40℃和60℃干燥处理(P0.05);总不饱和脂肪酸、油酸、亚油酸、十七碳烯酸、二十碳烷酸的比例及β-生育酚、δ-生育酚及总生育酚含量总体呈下降趋势,棕榈油酸、棕榈酸、硬脂酸的比例和β-谷甾醇、总甾醇含量总体呈升高趋势。低温干燥有利于提高杏仁油中生育酚含量,而提高干燥温度则有利于杏仁油中植物甾醇含量的提高。尤其是干燥温度为80℃以上时,杏仁油的品质变化加快。因此,为提高杏仁油理化与营养品质,杏仁脱皮后的干燥宜在80℃以下的较低温度条件下进行。研究结果可为杏仁干燥和高品质杏仁油加工提供参考。