利用缓冲容量检测苹果汁饮料中原果汁含量的方法研究

苹果汁饮料是1种缓冲溶液,其原汁含量不同则缓冲能力不同。本文对苹果汁饮料的缓冲系数与原果汁含量之间的关系进行了研究,结果表明:缓冲系数与原果汁含量呈线性正相关,同时得出了缓冲系数与原果汁含量之间的关系式。只要测定出该饮料的缓冲系数,即可根据关系式推算出该饮料中原果汁的含量。该方法的相对标准偏差0.56%～1.62%,回收率107%～113%,具有较高的准确度和精确度,且方法简便、快速,可用于苹果汁饮料中原果汁浓度的检测。     

杏汁饮料缓冲系数测定及缓冲盐对其影响的研究

杏汁饮料是一种缓冲溶液,其缓冲能力随杏浆含量不同而变化。对杏汁饮料的缓冲系数与杏浆含量之间的关系进行了研究,并初步探索了柠檬酸钠、六偏磷酸钠和三聚磷酸钠对其缓冲系数的影响。结果表明,缓冲系数与原浆含量之间呈线性正相关,得出了缓冲系数与原浆含量之间的关系式,以此推算出杏汁饮料中的原浆含量。该方法的相对标准偏差为0.11%～0.75%,回收率106.26%～112.70%,具有较高的准确度和精确度,方法简便,可用于杏汁饮料中原浆含量的快速检测。     

利用缓冲容量检测梨汁饮料中的果汁含量

梨汁是一种缓冲溶液，其含量不同则缓冲能力大小不同。文中对梨汁饮料的缓冲系数与原果汁含量之间的关系进行了研究。结果表明，缓冲系数与原果汁含量之间呈线性正相关，同时得出了缓冲系数与原果汁含量之间的关系式，根据此关系式可以推算出梨汁饮料中的原果汁浓度。该方法的相对标准偏差为0.60％～1117％，回收率107.21％～115.17％，具有较高的准确度和精确度，方法简便迅速，可应用于梨汁饮料原果汁浓度和真伪的检测。     

利用氨基态氮含量及缓冲能力检测葡萄汁饮料中原果汁含量的方法研究

通过对葡萄汁中氨基态氮含量与原果汁含量之间的关系,葡萄汁中的缓冲能力大小与原果汁含量之间的关系进行研究,结果表明:氨基态氮的含量与原汁含量呈正相关,且加入糖、酸后的原汁的氨基态氮含量不会变化;缓冲系数的大小与原汁含量呈正相关,且加入糖、酸后原汁的缓冲系数增大;同时得出它们之间的关系式。该方法简便、快速,可用于葡萄汁饮料中的原汁含量检测。     

缓冲能力与葡萄汁饮料中原果汁含量关系的研究

对葡萄汁饮料的缓冲系数与原果汁含量之间的关系进行了研究,结果表明,缓冲系数与原果汁含量呈线性正相关,同时得出了缓冲系数与原果汁含量之间的关系式。只要测定出该饮料的缓冲系数,即可根据关系式推算出该饮料中原果汁含量。该方法的相对标准偏差0.37%~1.13%,回收率106%~108%,具有较高的准确度和精确度,且方法简便、快速,可用于葡萄汁饮料中原果汁浓度的检测。     

用浊度法预测香蕉汁中混浊活性蛋白质和多酚

本研究采用浊度仪测香蕉汁混浊活性(HA)蛋白和多酚含量。为减少内源性蛋白和多酚的影响,分别用聚乙烯吡咯烷酮(polyvinyl polypyrrolidone, PVPP)和膨润土吸附多酚和蛋白质。将单宁酸加入PVPP处理与未处理香蕉汁中,果汁浊度变化与蛋白质含量呈线性相关,在蛋白质含量相同情况下,PVPP处理果汁的浊度较未处理样品小。热处理添加适量明胶的香蕉汁可反映果汁中HA多酚的含量,膨润土处理与未处理系列样品的浊度与其HA多酚含量呈线性相关。浊度法可用于测定香蕉汁中HA蛋白和HA多酚。     

我国果汁工业生产中的浸提工艺现状

我国果汁工业生产中的浸提工艺现状曹雁平，吴红北京轻工业学院在浓缩果汁、果汁、果汁饮料的生产中都有制汁操作［１］［２］。从水果中制取果汁最古老、应用最广泛的方法就是破碎榨汁法。对于不同的水果采用的破碎榨汁方法略有不同。对柑桔类多采用整果或半果榨汁；对于...     

柑桔汁的杀菌浓缩工艺及设备

<正> 柑桔汁是柑桔水果加工的主要产品之一,无论是原果汁、浓缩果汁或各种配制饮料,在国外均有广阔的销售市场。尤其是浓缩果汁,由于其可溶性物质含量高、便于运输、贮藏和节约包装,同时又是配制各种柑桔饮料的主要原料,故市场需求量很大。在国外,浓缩柑桔汁的生产已有四     

利用溶液缓冲能力测定龙眼汁饮料中原汁含量的方法研究

根据龙眼汁是一种缓冲溶液,其含量不同则缓冲能力大小不同,即由龙眼汁调配的龙眼汁饮料的溶液pH随添加的柠檬酸量的变化幅度不同,设计实验得出龙眼汁饮料的缓冲系数与其中龙眼汁含量的关系式,根据该关系式可以推算出龙眼汁饮料中龙眼汁的含量。     

果汁萃取工艺的可行性研究

<正>传统的果汁加工方法是以压榨法取汁,只有含汁液较少的水果(如山楂)和相对较软的水果(如草莓)例外.不仅提汁率低,还会将水果中的非果汁性成分(如果肉颗粒等)榨出,对果于加工的后序操作,特别是澄清过程带来     

Chemical composition of juice and seeds of pomegranate fruit

The edible parts of pomegranate fruit represented 52% of total fruit weight, comprising 78% juice and 22% seeds. The fresh juice contained 85.4% moisture, 10.6% total sugars, 1.4% pectin, 0.1 g/100 ml total acidity (as citric acid), 0.7 mg/100 ml ascorbic acid, 19.6 mg/100 ml free amino nitrogen and 0.05 g/100 ml ash. Meanwhile, the seeds are a rich source of total lipids, protein, crude fibers and ash representing 27.2, 13.2, 35.3 and 2.0%, respectively, and also contained 6.0% pectin and 4.7% total sugars. The iron, cupper, sodium, magnesium and zinc contents of the juice were lower than those of seeds, except potassium which was 49.2 ppm in the juice. On the other hand, the physical and chemical properties of seed's lipids indicated that the refractive index was 1.518, melting point 13.0°C, iodine value 74.2, acid number 1.1, unsaponifiable matters 0.7%, saponification value 188.9, ester value 187.8 and glycerol content 10.3%. Moreover, the studied lipids contained 11 fatty acids, from them caprylic, the predominant acid, represented 36.3%, followed by stearic acid (22.5%). Furthermore, oleic and linoleic acids covered 5.1% and 10.3%, respectively. Otherwise, the saturated fatty acids of seed's lipids of pomegranate composed 83.6% of the total fatty acids content.     

Temperature sums experienced before harvest partially determine the post‐maturation juicing quality of oranges grown in the Murrumbidgee Irrigation Areas (MIA) of New South Wales

Fruit acid levels are important to maturity standards for both fresh fruit and juice acceptability for processing oranges. Citrus fruit maturity standards are based on sweetness (Brix), titratable acidity (% acid) and their ratio. Harvest of Navel oranges for fresh juice can extend for up to 3 months (August–October) and for as long as 7 months (November–June) for Valencia oranges after they first reach acceptable fresh market maturity. Juice processors encourage ‘late hanging’ of fruit on trees to secure a continuous supply of fresh juice. During this time, gradual changes occur in % acid, Brix and juice content. This study tested the hypothesis that a significant proportion of the variation in fruit quality late in the harvest season could be accounted for by environmental conditions during the period that the fruits were left on the trees. Fruit juice quality was assessed in terms of Brix and % acid at the time of harvest for 19 000 fruit deliveries during a 9 year period from 1988 to 1996. The relationship between quality (Brix and acid content) and temperature sums (effective heat units—EHUs) for the period the fruits were held on the trees was tested. A temperature sum (‘day degree’) model for predicting relative changes in acid and Brix content of late‐harvested fruit was developed for both Valencia and Navel oranges. The juice acid relationship with EHUs was stronger than the Brix relationship with EHUs. In addition, the seasonal ‘behaviour’ of % acid was more consistent than that of Brix in both Valencia and Navel oranges. A linear reduction in % acid with increasing EHUs was evident in both varieties. Estimates of fruit quality (Brix/acid ratio) at harvest time should be made using the equations describing changes in % acid with EHUs and the relationship between Brix and % acid to determine Brix. These equations have potential use in predicting the internal quality of citrus fruit during extended harvest periods. EHU‐based fruit quality estimates could determine harvest schedules that enable growers to achieve the optimum factory price for their fruit whilst maximising returns to processors through more efficient product utilisation. © 2000 Society of Chemical Industry     

基于柑橘的多酵母协同发酵料酒的制备

为研究开发新风味调味料酒,本文采用具有特有风味品质的柑橘作为主体原料,分析了柑橘果肉汁和柑橘皮汁对酿酒酵母、鲁氏酵母和球拟酵母发酵的影响,优化了初始碳源和氮源条件,建立了多酵母协同混合发酵料酒的新技术。在添加160 g葡萄糖和10 g酵母浸粉的1000 mL全柑橘肉汁(去皮榨汁)中,发酵初期添加2%酿酒酵母,隔24 h添加2%球拟酵母,并在第48 h加入2%鲁氏酵母。在此最适条件下30 ℃静置发酵168 h后,所制备的柑橘料酒中乙醇和乳酸的浓度分别为145.00和0.11 mg/mL。本文为柑橘料酒产品的开发奠定了基础。     

不同原料果酒发酵工艺研究

研究苹果汁、梨汁、葡萄汁、柑橘汁发酵过程中糖度和酒精度的变化和影响因素。结果表明,原料不同,发酵温度不同,糖度下降速率、发酵过程最高酒度值存在一定差异,pH值、原料质量也会影响果酒质量及出酒率。     

基于原料与果汁品质的蓝莓果实加工性能评价

以‘蓝金’、‘瑞卡’、‘N5’等12个辽南露地栽培蓝莓品种果实为试材,通过果实外观、营养品质及加工性能指标的观测与分析,筛选加工适宜品种。结果表明,蓝莓果实以蓝色为主,呈不同程度扁球形,表面附着果粉,单果重0.95~2.63 g;含水量>80%,果越大,含水量越高,果型越扁,果实中均含有果糖、葡萄糖、草酸、奎尼酸、苹果酸、莽草酸和柠檬酸,果糖与葡萄糖含量相当,柠檬酸含量显著高于其它有机酸（P<0.05）,属于已糖积累型、柠檬酸优势型果品。供试品种果实中均含有钾、镁、钙、铁、锰、锌和铜元素,含量依次递减,钾含量最高（5786 mg?kg?1）,极显著高于其它元素（P<0.01）,‘达柔’果实中钾含量（7400 mg?kg?1）最高。不同品种果实不添加果胶酶处理出汁率差异极大（变异系数达60.42%）,添加果胶酶处理出汁率差异很小（变异系数仅3.88%）,添加果胶酶处理出汁率及果汁可溶性糖、可滴定酸含量明显提升,添加果胶酶处理能够提高果汁产率和质量。果实中果糖和葡萄糖含量越高,果汁中可溶性糖含量越高（相关系数为0.96和0.98）;果实中柠檬酸和奎尼酸含量越高,果汁中可滴定酸含量越高（相关系数为0.81和0.71）。‘日出’、‘蓝金’和‘北卫’3个品种可溶性糖（>90 mg?g?1）、有机酸含量（>10 mg?g?1）和出汁率（>74.6%）均较高,是较好的加工品种。综上,‘日出’、‘蓝金’和‘北卫’3个品种果实营养丰富、出汁率高,是加工的理想原料。     

Bergamot: A source of natural antioxidants for functionalized fruit juices

Bergamot is a common Italian citrus fruit, cultivated almost exclusively to produce essential oils; the juice is considered a waste product, which represents a serious environmental and economic problem for the industries. The aim of this study was to re-evaluate bergamot juice through its chemical characterization and its use to enrich and fortify fruit juices. To investigate this, apples and apricots were used for the laboratory-scale production of fruit juice, following both the traditional industrial recipe and those with the addition of bergamot juice at 10% or 20%, together with or in order to replace the synthetic additives normally used in the industrial process (ascorbic acid and citric acid). The ascorbic acid content and the antioxidant activity were measured during the different steps of juice production and after storage at 37 °C for 15 days to evaluate juice shelf-life. Apricot and apple juices fortified with bergamot juice showed a significant increase in their antioxidant properties and a decreased reduction in ascorbic acid content after the typical production steps. All of the results obtained support the hypothesis that the addition of bergamot juice to juices preserves their ascorbic acid content from thermal degradation and contributes to enhance the antioxidant activity, ensuring a product much richer in antioxidants and ascorbic acid. A preliminary consumer test encouraged the production of bergamot fortified fruit juices. Finally, this is the first time that isorhoifolin and rutin have been detected in bergamot juice.     

四种不同发酵基质柑橘果醋挥发性成分分析

为了研究四种不同发酵基质柑橘果醋挥发性成分的差异,分别以食用酒精发酵柑橘果醋（EACV）、酒醋连续发酵柑橘果醋（WVCV）、酒汁混合发酵柑橘果醋（WJCV）和酒水混合发酵柑橘果醋（WWCV）四种不同发酵基质的柑橘果醋为研究对象,利用电子鼻和顶空-固相微萃取气质联用技术（HS-SPME-GC-MS）,分析不同发酵基质的柑橘果醋挥发性成分的种类和含量。结果表明,四种柑橘果醋中共检测出138种挥发性成分,包括酯类物质34种、醇类物质37种、酸类物质20种、醛类物质8种、酚酮类物质13种、烃类物质10种和其他类物质16种。挥发性成分总含量高低依次为：WVCV＞WWCV＞WJCV＞EACV,其中EACV保留了更多柑橘果汁的气味,其他三种果醋风味更加浓郁。     

Concentration of morpholine residues in major fruits and juices and its dietary exposure in China

Morpholine is a common chemical used as emulsifier in the preparation of wax coatings for some fruit to help them remain fresh and protect against insects and fungal contamination. It has been reported that morpholine has acute toxic effects on rodents. In the present study, morpholine concentrations were analysed in fruits (citrus fruits, apples, strawberries and grapes) and juices (apple juice and orange juice) in order to determine dietary exposure among the Chinese population. A total of 732 fruit and juice samples were collected during 2015–2016, which covered major foods in China. Fruit and juice consumption data were taken from China National Nutrient and Health Survey (2002) and include data from 16,407 fruit or juice consumers. It was found that mean dietary exposure to morpholine residues from fruits and/or juices for general Chinese consumers and children 2–6 years old were 0.42 and 1.24 µg/kg bw/day, respectively. The 97.5% intake in general Chinese consumers and children 2–6 years old were 2.25 and 6.90 µg/kg bw/day, respectively. The primary food sources of the morpholine dietary intake of general Chinese consumers were citrus fruits (57.4%) and apples (40.8%). These findings suggested that dietary exposure to morpholine in the Chinese population was lower than the acceptable daily intake of morpholine, and there are no health concerns.