Storage Stability of Orange Juice Concentrate Packaged Aseptically

Orange juice concentrates were packaged aseptically by a “Dole” aseptic canning machine using 6 oz metal cans. The final juice products (11°, 34°, 44°, 58° Brix) were stored between ?18° and 36°C and tested periodically for nonenzymatic browning, ascorbic acid destruction, furfural and sensory changes. Nonenzymatic browning, the main deterioration phenomena in these products, was satisfactorily retarded at 12°C or lower. Ascorbic acid destruction rate constant was dependent on temperatures between 5 and 25°C, and was affected by degree of juice concentration. Furfural accumulation in juice was higher than that in 58° Brix concentrate. Orange juice concentrate of 58° Brix did not show flavor changes after storage at 5°C or 12°C for 17 or 10 months, respectively, when evaluated after reconstitution to 11° Brix.     

浓缩橙汁贮藏过程中非酶褐变的研究

研究了浓缩橙汁在不同贮藏条件下与非酶褐变有关的主要物质的变化及其与褐变的关系。通过相关性分析和通径分析,探求引起浓缩橙汁褐变的主要原因。实验表明,抗坏血酸的氧化降解,类胡萝卜素的降解,酚类物质的氧化缩合是引起褐变的主要因素,美拉德反应对褐变的影响较小。     

Preparation and Storage of 72° Brix Orange Juice Concentrate

Each year, thousands of tons of citrus concentrate are stored and transported throughout the world at 62° Brix. Increasing this concentration to 72° Brix can result in substantial savings. Fresh orange juice, treated mechanically or with pectic enzymes to reduce its viscosity, was concentrated to 72° Brix in a commercial processing plant, then samples were stored in barrels in a tank farm at ?7 or at 4°C. At monthly intervals, samples were blended to make 41.8° Brix Frozen Concentrated Orange Juice. The enzyme-treated samples had lower viscosity than those mechanically treated. Vitamin C retention levels were > 94% after 6 months storage at 4°C. Taste evaluations rated the product ‘very good’ and furfural levels were well below that which indicates off flavors. Browning tended to increase with storage time and temperature.     

外源因子对贮藏橙汁色泽影响研究

对冰糖橙汁中的主要成分(抗坏血酸、还原糖、酚类化合物、金属离子和游离氨基酸等)进行了定量分析;选择L(+)抗坏血酸、葡萄糖、果糖、Fe2+、Cu2+与Fe3+作为外源因子添加到橙汁中,比较其对贮藏橙汁色泽的影响。结果表明:所添加的外源成分对贮藏橙汁色泽的变化都有不同程度的影响,其中以抗坏血酸影响最为显著,果糖和葡萄糖的影响相对较小;铁离子、铜离子均具有促进橙汁非酶褐变反应的作用,Fe3+和Cu2+的促褐变活性强于Fe2+。     

水煮藕带贮藏期非酶褐变的主要影响因素探究

为了探究水煮藕带在贮藏期间与非酶褐变有关的主要物质变化规律及主要反应类型,分别使用了两种不同透氧率的包装袋对水煮藕带进行真空包装和为期60 d的贮藏.结果表明:包装袋透氧率越高,藕带的褐变程度越深;结合多元统计分析中的主成分分析和相关性分析方法,阐释了高透氧袋处理组藕带贮藏期间致褐变因子与色泽参数变化之间的关系,第一主...     

马水橘贮藏保鲜研究

对马水橘果实进行湿冷及臭氧处理贮藏保鲜研究.试验结果表明:在贮藏库内温度为6℃～8℃、相对湿度88%～90%及臭氧浓度5 mg/m3～10 mg/m3的贮藏条件下,经过90 d的贮藏后,湿冷、臭氧处理、套袋及不套袋处理的果实,病烂率、失重率最低,主要营养成分损失最少,贮藏保鲜效果最好.     

基于UPLC-QTOF-MS代谢组学技术的NFC和FC橙汁差异成分比较

为比较非浓缩复原(not from concentrate,NFC)橙汁和复原(from concentrate,FC)橙汁的成分差异,采用非靶向代谢组学技术对2种果汁进行分析.利用超高效液相色谱-四极杆串联飞行时间质谱仪在正离子和负离子模式下采集样本的代谢物信息,通过正交偏最小二乘判别分析实现了对NFC和FC橙汁的区...     

影响花生牛轧糖储藏品质的关键因素分析及改进方法研究

为确定花生牛轧糖储藏过程中哈变的原因及其改进方法,研究分析不同温度条件下储藏的带壳和脱壳花生的氧化稳定性以及添加经不同方式处理的花生制备的牛轧糖品质.结果表明:在室温(25℃)、37、60℃下储藏过程中,带壳花生比脱壳花生氧化速度慢,在室温下储藏58 d后,带壳生花生的过氧化值均无明显变化且始终小于2 mmol/kg;...     

肉制品冷藏过程中热异味的产生及影响因素

热异味(WOF)是肉制品在加热-冷藏-再热过程中由于肌内磷脂的自动氧化引起的,也是肉制品在贮藏过程中质量败坏的主要原因之一,为了更好地控制热异味的产生,综述了肉制品中热异味的产生原因、影响因素及控制措施。     

冷冻鱼糜蛋白在冻藏中的物理化学变化及其影响因素

较详细论述了冷冻鱼糜蛋白在冻藏过程中因变性而发生的一些重要的物理化学变化，包括肌原纤维蛋白的盐溶性，ATP酶活性，活性巯基，总巯基及二硫键的含量，表面疏水性，粘度等的变化，并在此基础上论述了鱼的鲜度，pH值，漂洗条件，冻结及解冻条件等对这些变化的影响，从分子水平分析了鱼糜蛋白的冷冻变性机理。     

基于PCR-CE技术的NFC橙汁与FC橙汁鉴别

摘 要：以特洛维塔、早金、哈姆林3 种甜橙为原料,按照市售橙汁的主要生产工艺,模拟制备非复原（not from concentrated,NFC）橙汁和复原（from concentrated,FC）橙汁。针对甜橙叶绿体成熟酶K蛋白基因（maturase K,matK）和烟酰胺腺嘌呤二核苷酸脱氢酶基因（nicotinamide adenine dinucleotide dehydrogenase,ndhF）,共设计8 对引物用以扩增得到不同长度的目标条带,结合聚合酶链式反应（polymerase chain reaction,PCR）和毛细管电泳（capillary electrophoresis,CE）技术分析了鲜榨、均质、巴氏杀菌、浓缩、二次巴氏杀菌关键加工工艺,对特洛维塔橙汁叶绿体matK和ndhF基因的DNA降解变化的影响,探讨NFC橙汁与FC橙汁DNA降解程度的差异,筛选出NFC橙汁和FC橙汁的特征差异性片段组,建立基于PCR-CE技术的NFC橙汁与FC橙汁鉴别方法。该方法适用于分析货架期内的NFC橙汁与FC橙汁,且同样适用于早金和哈姆林甜橙为原料的NFC橙汁与FC橙汁的鉴别。应用该方法对市售NFC橙汁进行检测,发现市售NFC橙汁存在标签不符的现象。本研究建立的基于PCR-CE技术的NFC橙汁与FC橙汁定性鉴别方法可以为果汁行业的有效监管提供技术支撑。     

Storage Stability of Carotenoids in Orange Oil

Citrus essential oils are used as flavoring agents in foods and beverages. Recently a premium price was paid for oils with a high carotenoid content because they were also used as natural coloring agents. Commercially manufactured samples of ‘Pineapple’ oils were concentrated 5, 10, and 25-fold, stored for 12 moat –18, 4, 26, and 32°C and sampled periodically. The carotenoid content was measured spectrophotometrically with β-carotene as a standard. From an initial value of 7.2 mg of β-carotene/100g of oil, it decreased 6.6, 18.4, and 24.6% upon concentrating 5, 10, and 25-fold, respectively. The 25-fold sample lost 6% of its β-carotene at –18°C and 90% at 32°C during 12 mo of storage. There was a highly significant fit of the time, temperature and concentration data to a second order model.     

橄榄果实冷藏期间失重影响因素的研究

对福建省10个主栽橄榄品种果实在8℃、RH85%贮藏条件下的果实失重率及贮藏温度(2℃、6℃、10℃、20±1℃室温)、贮藏时间及包装对果实失重率的影响进行研究.结果表明,橄榄各品种随贮藏天数的增加,果实失重率呈线性增加;供试的10个橄榄品种,以中长营最易失水,福州品种群大长营、中长营、小长营较容易失水,莆仙品种群厝后本、刘族本保水性能较好,其中刘族本果实失重率显著(P<0.05)地低于其它品种果实.没有包装的檀香橄榄果实失重率与贮藏温度、贮藏时间呈显著(P<0.05)正相关,即橄榄果实失重率随贮藏温度升高(相关系数r=0.9560～0.9999),贮藏时间延长(r=0.9692～0.9960)而增加,且它们间存在互作效应,橄榄不同品种与贮藏时间之间也存在互作效应.用0.04mm厚聚乙烯薄膜袋包装,可有效地控制橄榄果实的自然失水,与对照组没有包装间存在极显著(P<0.01)差异,因而延长了橄榄果实贮藏期.     

血橙果汁贮藏过程中品质变化研究

通过血橙原汁成分分析,对血橙原汁低温贮藏过程中与品质相关的几项指标的变化进行监测,以探讨低温贮藏对血橙果汁品质的影响。结果表明：血橙汁富含花色苷(68.84mg/L)、黄酮类物质(0.18mg/mL)、抗坏血酸(0.63mg/mL)、氨基酸(43.012mg/mL)、糖类(128.3mg/mL)等物质,还含有Ca、Mg、Zn、Fe、Cu 等丰富的人体必需微量元素;同时HPLC 分析显示血橙汁含有的可溶性糖主要是蔗糖(7.4g/100mL)、果糖(2.2g/100mL)、葡萄糖(2.1g/100mL)。在血橙汁贮藏过程中,随着花色苷含量的下降橙汁鲜艳的红色也逐渐褪色成浅黄褐色,抗坏血酸含量明显下降,贮藏40d 后含量下降约52%;而还原糖含量变化缓慢,总酸含量平缓增加。     

Factors Affecting 1-Octen-3-ol in Mushrooms at Harvest and During Postharvest Storage

Harvesting experiments revealed that immature whole mushrooms with closed veils had higher 1-octen-3-0l levels than more mature whole mushrooms with open veils. The l-octen-3-01 content of the gills was higher in immature mushrooms with closed veils, gradually decreased with maturity as the veil opened, and finally increased after the gills were well exposed. Postharvest experiments demonstrated that storage temperature influenced the activity of lipoxygenase-hydroperoxide lyase, but no differences in 1-octen-3-01 content were observed. Enzyme activity as well as 1-octen-3-01 content decreased during storage. Addition of calcium chloride to irrigation water, employed to improve quality and shelf life of fresh mushrooms, increased the amount of l-octen-3-01 immediately after harvest.     

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.     

果蔬气调库快速降氧时间的影响因素

为了使果蔬尽早进入气调状态,达到提高贮藏品质的目的,作者对影响气调库快速降氧时间的因素进行了研究。以西安某苹果气调库为研究对象,采用k-ε紊流模型建立了气调库内气体流动、传热与传质的三维数学求解模型,并通过编写UDF程序获得苹果呼吸强度和冷风机送风口O_2、CO_2质量分数随库内气体组分体积分数变化实时数据。通过改变制氮机工作参数和果蔬品种对该气调库的充氮降氧过程进行数值模拟,获得库内O2体积分数随时间变化的规律,并与实验数据呈现较好的一致性。结果表明:不同的氮气纯度对应着相应的最快降氧区间。作者研究对象选择体积分数为96%的氮气所需降氧时间最短,呼吸强度差别较大的果蔬降氧时间有明显差异。     

Causes of Browning in Pear Juice Concentrate During Storage

Pear juice was treated with cation exchange resin, PVPP, XAD-4, oxygen, and various resin combinations. Samples were concentrated and increases in browning measured during storage at 37°C. Analytical determinations included α-amino nitrogen, total phenolics, metal ions, ascorbic acid, and dehydroascorbic acid. While XAD-4 and PVPP were more effective in lowering phenolic content and reducing initial color, cation exchange treatment removed amino acids and was most effective in preventing browning and providing flavor stability. Addition of glycine to cation-exchange treated samples restored browning rates. Reductone formation during storage resulted in an apparent increase in ascorbic acid. It was concluded that Maillard browning reactions predominated during storage.     

核磁共振技术(NMR)研究脐橙的储藏过程

本实验采用低场核磁共振技术研究不同处理方法脐橙在储藏过程中水分的变化以及水分的迁移行为,同时结合理化分析,探讨脐橙储藏过程中磁共振参数与脐橙品质变化的相关性。实验结果发现,果蜡处理的脐橙在四种方法中具有最高的T2弛豫时间,2,4-D处理的变化较缓。从T2数据结合理化性质分析可得,空白清水处理的样品货价期最短,其它方法处理的脐橙有较长的货架期;大分子物质降解为小分子物质,果皮失去持水能力,自由水分的生成大于自由水分的消耗是脐橙腐败的主要影响因素。