壳聚糖对酸樱桃果汁的澄清效果

以壳聚糖为澄清剂对酸樱桃果汁进行澄清处理。在单因素试验的基础上,采用Box-Behnken响应面设计,研究了壳聚糖添加量、作用时间和作用温度对酸樱桃果汁澄清效果的影响。确定适宜的工艺参数是:壳聚糖添加量0.6 g/L、作用时间35 min、作用温度44℃。此工艺条件下处理的酸樱桃果汁,浊度为0.37 NTU,可溶性固形物含量为12.0%,果胶未检出。     

蓝靛果汁花色苷热降解动力学的研究

以新榨蓝靛果汁为试材,采用控制温度、调节pH值、连续充N2等方法,探讨蓝靛果汁花色苷的热降解动力学,为深加工条件的优化控制及保质期的预测提供科学的依据。结果表明:蓝靛果花色苷对热不稳定,花色苷的降解过程符合一级动力学反应。随着pH值和温度的升高,蓝靛果花色苷的热降解半衰期(t1/2)和活化能(Ea)显著下降,研究表明充氮气处理可以提高蓝靛果花色苷的稳定性。     

桑葚花色苷的分离纯化及其热降解动力学研究

通过AB-8大孔树脂、乙酸乙酯萃取和Toyopearl TSK HW-40S凝胶柱层析对桑葚汁中的花色苷进行分离纯化,得到两个单一的化合物组分。经HPLC-MS鉴定这两种花色苷分别为矢车菊素-3-芸香糖苷和矢车菊素-3-葡萄糖苷。在此基础上,研究了不同纯度花色苷的降解动力学,结果表明:桑葚花色苷粗提物中所含的黄酮类化合物对花色苷的热降解有较强的保护作用,含黄酮的花色苷体系对p H值的变化更为敏感。在p H 3.5时,矢车菊素-3-芸香糖苷和矢车菊素-3-葡萄糖苷的热稳定性基本相同;在p H 4.0时,矢车菊素-3-芸香糖苷的热稳定性略好于矢车菊素-3-葡萄糖苷。     

草莓浑浊汁花色苷热降解动力学

为建立草莓浑浊汁花色苷降解动力学模型,在不同pH值、温度和加热时间对草莓浑浊汁花色苷残留率进行测定试验.结果表明:随温度和pH值的升高,其降解速率明显加快,草莓浑浊汁花色苷热降解符合一级动力学反应,在pH值为3.3时,其反应活化能Ea为63.69 kJ/mol,反应常数A为1.24×109,该模型的预测值与实测值的相关系数达0.9876,表明该模型有效.     

苹果汁中维生素C热降解动力学研究

为了探索温度对苹果汁中维生素C降解的影响以及维生素C的降解动力学规律,采用可逆的一级反应模型,对加热温度30、40、50、60、70℃条件下苹果汁中还原型维生素C(AA)和氧化型维生素C(DHA)含量的变化及降解动力学进行了研究,结果表明:60℃的AA反应速率最大,DHA反应速率基本随着温度升高而增大;温度升高,可逆反应速率常数增大,其它降解途径速率常数变化不明显;AA无氧氧化速率与温度有一定关系,50℃的AA无氧氧化速率最大,70℃的AA无氧氧化速率最小;AA和DHA热降解反应活化能均低于一般化学反应活化能,说明苹果汁中维生素C热稳定性较差。维生素C的降解主要是有氧氧化反应,苹果汁中维生素C无氧降解速率比有氧降解速率慢;温度升高,苹果汁中维生素C有氧降解速度加快,无氧降解速度变化不明显。在苹果汁加工工艺中应尽量隔绝氧气,采用高温(70℃)短时热处理。对成品苹果汁应采用低温贮藏。     

Kinetics of Thermal Degradation of the Anthocyanins Delphinidin-3-rutinoside and Malvidin-3-glucoside

The kinetics of the thermal degradation of the two anthocyanins delphinidin-3-rutinoside and malvidin-3-glucoside at 78, 88, 98 and 108 °C, depending on the pH and the type of solvent has been investigated. The first order reaction of delphinidin-3-rutinoside and malvidin-3-glucoside degradation has been established. The rate constants (K ± 10^?5s^?1), the activation parameters, factor Q₁₀ and the half-decay period have been calculated. The rate of delphinidin-3-rutinoside degradation is higher than that of malvidin-3-glucoside.     

樱桃花色苷的提取及抗氧化活性研究

采用酸化乙醇法提取樱桃中的花色苷,通过单因素试验研究酸化乙醇体积分数、浸提温度、料液比、浸提时间和浸提次数对花色苷提取量的影响,并测定樱桃花色苷提取物的抗氧化活性.结果表明:以pH 3的80％乙醇溶液,料液比1:7,30℃浸提樱桃果肉2h,提取2次,花色苷提取量为26.01 mg/100g(鲜果).当花色苷质量浓度在0.031～0.5 mg/mL范围时,樱桃花色苷提取物的抗氧化能力随着浓度的增加而增加,其中对羟基自由基和超氧阴离子的抑制率最高分别达到79.56％和50.7％.     

Pressure Degradation Kinetics of Anthocyanin Pigment and Visual Color of Chinese Bayberry Juice

Pressure degradation kinetics of the anthocyanin pigment content and visual color (L, a, and b values) of Chinese bayberry juice were evaluated at selected pressures (400, 500, and 600 MPa) and holding times (5–10 min). Results indicated that the degradation of anthocyanin content after high pressure processing and during storage followed the first-order models, as well as the change of a and L × a × b values after high pressure processing. The activation energies (V_a) for anthocyanin content, a and L × a × b changes after high pressure processing were –19.845, –14.915, and –12.908 cm³ mol^–1, respectively. V_a analysis indicated that anthocyanin was more pressure sensitive than visual color parameters.     

蔗糖含量对牡丹花色苷贮藏稳定性和降解动力学的影响

研究蔗糖含量对牡丹花色苷贮藏稳定性的影响.花色苷降解动力学数据的分析结果表明,牡丹花色苷在20℃和37℃贮藏条件下的降解符合一级反应动力学模型,花色苷半衰期随贮藏温度降低而延长;褐变指数随贮藏温度的升高和贮藏时间的延长而增大.加入蔗糖,提高牡丹花色苷的贮藏稳定性,表现为花色苷的降解速率常数减小,半衰期延长,褐变指数减小.含糖花色苷样品液的降解速率常数和褐变指数依次为:62<30<45<11°Brix.     

Stabilization of Anthocyanins of Blood Orange Fruit Juice

The stability of the red color of pigmented orange fruit juice was somewhat improved by pasteurization with microwaves and addition of tartaric acid and gluthathione as mildly acidic and antioxidant agents, respectively. Highest stability was obtained through the formation of complexes between anthocyanins and phenolic compounds, such as rutin and caffeic acid.     

Photochemial Degradation of Betanine and Selected Anthocyanins

The effect of fluorescent light on the degradation rates of betanine and the major cranberry anthocyanins was determined in model systems. Degradation rates were measured in the presence of oxygen in a temperature range 25–55°C. Retained pigment was separated and quantified by high performance liquid chromatography. Light had a minimal effect at 55°C because of considerable thermal destruction. However, at 40°C for anthocyanins and 25°C for betanine, light was responsible for most of the degradation occurring. Light increased rates of anthocyanin degradation more than those of betanine. Molecular oxygen was necessary for light to have a significant effect.     

Thermal Degradation of Acylated and Nonacylated Anthocyanins

ABSTRACT:  The thermal degradation pathways of acylated and nonacylated anthocyanins from 3 commercial sources have been investigated. Strawberry, elderberry, and black carrot concentrates were purified on XAD-16-HP and Sephadex-LH-20 columns to remove sugars, amino acids, salts, and phenolic compounds, respectively. The so obtained anthocyanin isolates were heated at 95 °C at pH 1, the optimum stability condition for the flavylium cation. During 7 h of thermal exposure, the samples were monitored by HPLC-DAD-MS³ at 280, 320, and 520 nm, respectively, together with spectrophotometric color and anthocyanin assessment. Total anthocyanin content lightness, and chroma, but not hue angle, were appropriate parameters to monitor anthocyanin loss on a statistically significant level. Anthocyanin glycosides were generally cleaved by successive loss of sugar moieties and pentoses were more readily split off than hexoses. Anthocyanin aglycones were further degraded by scission into phloroglucinaldehyde (cyanidin, pelargonidin), 4-hydroxybenzoic acid (pelargonidin), and protocatechuic acid (cyanidin), the residues of the A- and B-rings, respectively. Most interestingly, acylated cyanidin-triglycosides from black carrot were degraded into their corresponding diglycoside derivatives, which are not genuine carrot pigments. Moreover, hydroxycinnamic acid glycosides were generated. It is therefore assumed that the thermal burden during processing of anthocyanic food can be deduced by monitoring the colored and colorless compound profiles.     

Clarified Natural Apple Juice: Production and Storage Stability of Juice and Concentrate

Thermal treatment (90°C, 20 sec) of Red Delicious apple mashes followed by Pectinase (0.02%;v/w), centrifugation, bentoniting and filtration resulted in a clear natural apple juice. Whole apple mash juice was faintly pink due to extracted skin anthocyanins and the 70° Brix concentrate prepared from the juice was ruby red. Pink juice browned extensively over 648 hr storage at 37°C and browning was associated with development of an absorption maximum at 446 nm. The ruby red concentrate stored at 37°C, turned orange (167 hr) darkening to brown (648 hr) and gave visible spectral scan typical of Maillard browning development.     

HACCP系统在胡萝卜浓缩汁生产中的应用

胡萝卜浓缩汁富含人体所需的维生素、氨基酸和β-胡萝卜素(维生素A源),对防癌、治癌、婴幼儿发育、排毒、养颜及视力保护有良好的保健功效。将HACCP体系应用于胡萝卜浓缩汁的生产管理,不仅可以提高产品     

Nonenzymatic Browning in Apple Juice Concentrate during Storage

Rate of browning in Red Delicious and Granny Smith apple juice concentrates during storage was investigated. Color development at 65°, 70° and 75°Brix and storage temperatures of 5°, 20° and 37°C were compared over 120 days. Color deterioration occured at a faster rate in Red Delicious. Reaction at different concentration and storage conditions was exponential, following an Arrhenius-type dependence with temperature. Activation energy for a solids content of 65 - 75°Brix ranged from 16.4 - 19.3 Kcal/mole. Influence of juice variety on activation energy was negligible. Water activity results are in general agreement with those reported by other investigators. A satisfactory correlation to predict commercial concentrate browning has been obtained. All other things being equal, thermal history is a critical factor to obtain a lighter color concentrate.     

青梅原汁的生产工艺研究

确定了青梅原汁的生产工艺流程和参数。青梅果应选择成熟度高于九成五以上;预煮条件为90℃,3min;果胶酶解条件为果胶酶A 50mg/kg和B 100mg/kg,在40℃下酶解12h;杀菌条件为121℃处理3s～5s。     

苹果浓缩汁中酚类物质提取方法

建立儿茶素、绿原酸、咖啡酸、表儿茶素、香豆酸、阿魏酸、芦丁、根皮苷8种物质的高效色谱测定体系,并对不同pH处理下和不同溶剂提取出的8种小分子酚类物质的相对回收率进行比较,结果表明:在所测定的苹果浓缩汁中的8种酚类物质中,有5种在pH=2.0提取、50%甲醇溶解时有较高的相对回收率.     

Physical-Chemical Characteristics of Partially Clarified Guava Juice and Concentrate

Partially clarified guava juice concentrate was prepared from single strength guava puree (5.5°Brix) by treatment with pectinase (2 hr at 50°C), extraction of juice with a rack-and-cloth press, and vacuum concentration to 23°Brix. The concentrate had the following characteristics: density, 1.10; pH, 3.16; total acids, 4.67%; ash, 1.51%; moisture, 72.4%; ascorbic acid, 867 mg%; viscosity, 4.4 cp; and CIE L* 39.2, CIE a* 10.33, CIE b* 27.11.     

大樱桃果汁加工工艺研究

以新鲜的大樱桃果(红灯)为原料,研究大樱桃果汁的加工工艺。通过单因素试验确定大樱桃的最佳烫漂时间,正交试验确定果胶酶的适用条件。经过试验确定最佳的热烫处理条件为深红色大樱桃果烫漂10s,果胶酶的最适使用条件为:果胶酶添加量为0.20%,酶解时间120 min,酶解温度45℃,出汁率达到70.34%。     

大樱桃果汁加工工艺研究

以新鲜的大樱桃果(红灯)为原料,研究大樱桃果汁的加工工艺.通过单因素试验确定大樱桃的最佳烫漂时间,正交试验确定果胶酶的适用条件.经过试验确定最佳的热烫处理条件为深红色大樱桃果烫漂10s,果胶酶的最适使用条件为:果胶酶添加量为0.20％,酶解时间120 min,酶解温度45 ℃,出汁率达到70.34％.