Physicochemical Characteristics and Quality of Refrigerated Spanish Orange-Carrot Juices and Influence of Storage Conditions

ABSTRACT: The effects of the physicochemical and quality characteristics of various refrigerated mixed orange and carrot juices, and their changes with storage time and temperature were investigated. Density, dry extract, Brix values, acidity, turbidity, formol index, pectinmethylesterase, hydroxymethylfurfural, essential oils, ascorbic acid, and color varied with storage time and temperature. Some of the parameters could be used as indicators of quality loss or spoilage of the juices. The degradation of ascorbic acid corresponded to 1st-order kinetics. The shelf life of the juices was established at 4 °C and 50-d storage or at 10 °C and 32-d storage.     

Flavor Losses in Orange Juice during Ultrafiltration and Subsequent Evaporation

Losses of volatile compounds in orange juice during ultrafiltration and subsequent evaporation were studied. Alcohols and esters predominated in the permeate, while terpenes (d-limonene and valencene) and nonpolar aldehydes (octanal and decanal) were distributed in the retentate from the ultrafiltration (UF) system. Fractions of some flavor compounds were lost during ultrafiltration process. An aqueous phase essence was recovered from the permeate during evaporative concentration. No oil phase was observed. When whole juice was concentrated, both oil and aqueous phases were recovered. Essence recovery efficiency of individual compounds was 3 to 13% when concentrating permeate and <5% when concentrating whole juice.     

Dynamic Head Space Analyses of Orange Juice Flavor Compounds and Their Absorption into Packaging Materials

ABSTRACT: A simple, rapid, sensitive, and reproducible dynamic headspace gas chromatography (DH-GC) was developed to study the absorption of d-limonene, α-pinene, ethyl butyrate, and octanal into laminated polymeric packaging materials containing low-density polyethylene, polyethylene terephthalate, polyvinylidene chloride, and ethyl-ene-vinyl alcohol copolymers. The linear regression lines showed that the flavor compound peak areas were directly proportional to the concentrations of the standard flavor compounds with R ²≥ 0.97. The coefficients of variation for the DH-GC analyses were less than 4%. A test cell was designed to study orange juice flavor absorption into the packaging materials for 28 d at 25 °C. Ethyl butyrate or octanal absorption was not different among the 4 packaging materials ( P > 0.05). Addition of a polyethylene terephthalate and a ethylene-vinyl alcohol copolymer layer to the packaging materials reduced the d-limonene and α-pinene absorption by 20% and 50%, respectively.     

High Pressure Inactivation Kinetics of Saccharomyces cerevisiae Ascospores in Orange and Apple Juices

High pressure inactivation kinetics (D and z values) of Saccharomyces cerevisiae ascospores were determined in fruit juices and a model juice buffer at pH 3.5 to 5.0. Approximately 0.5 to 1.0 × 10⁶ ascospores/mL were pressurized at 300 to 500 MPa in juice or buffer. D-values ranged from 8 sec to 10.8 min at 500 and 300 MPa, respectively. The range for z-values was 115 to 121 MPa. No differences (P≥0.05) in D (at constant pressure) or z-values among buffers or juices at any pH were determined, indicating little influence of pH in this range and absence of protective or detrimental effects of juice constituents.     

Flavor, Viscosity, and Color Analyses of Hot and Cold Break Tomato Juices

ABSTRACT: Two methods are used commercially to produce tomato juice: hot break and cold break. Tomatoes were chopped and allowed to sit for various time intervals to simulate the cold break process. Zero was hot break, and 2 to 24 min represented cold break. Sensory, volatile, color, and viscosity analyses were conducted to determine which hold time produced the optimum juice. Sensory panelists rated 15 min cold break most fresh and liked over hot break. Lipoxygenase-initiated volatiles increased from hot to cold break. No overall color difference was found between hold times. Viscosity decreased from hot to cold break. The cold break process can be used to produce a premium flavored tomato juice.     

脐橙全果酒发酵工艺优化及其与脐橙果汁酒风味物质的对比分析

以脐橙全果为原料酿造脐橙全果酒,采用单因素试验和Box-Behnken试验设计,分析酵母接种量、发酵温度、发酵时间对脐橙全果酒发酵的影响。结果表明其最佳条件为：酵母接种量6.4%、发酵温度28 ℃、发酵14d。同时,采用顶空固相微萃取法、利用气相色谱-质谱联用技术对脐橙全果酒和脐橙果汁酒风味物质进行分析。结果表明：在脐橙全果酒和脐橙果汁酒中分别检出25 种和11 种挥发性香气物质,且脐橙全果酒的香气活性成分主要为萜烯类,占香气成分的66.00%,而脐橙果汁酒的主要香气成分为醇类,所占比例为91.95%。     

甜橙中不同活性成分与总抗氧化能力关系的研究

测定了7个甜橙品种果汁中主要活性成分,包括VC、多酚、总类胡萝卜素及类柠檬苦素的含量,VC的含量介于390.6～478.6mg/L之间,多酚类介于573.1～655.0mg/L,总类胡萝卜素介于5.47～7.25mg/L,类柠檬苦素介于0.10～0.17mg/L。用ABTS/K2S2O8体系测定的反映总抗氧化能力的TEAC值介于4.79～6.09之间,血橙最高,锦橙最低。TEAC值与VC的相关度达到显著水平（r=0.868,p=0.011）,与多酚类达到极显著水平（r=0.909,p=0.003）,而与总类胡萝卜素则无显著相关关系（p〉0.1）,表明多酚类物质可能是甜橙品种中主导的抗氧化活性成分。     

超声波对橙汁的杀菌特性研究

以鲜榨橙汁为原料,研究了超声波在不同橙汁特性以及仪器可变条件下,对菌落总数的影响,通过正交试验结果得出杀菌的较优条件是：杀菌时间：13min,振幅：70％,脉冲时间on：30s,脉冲时间off．25s、处理量：50ml;方差分析结果表明,杀菌时间、振幅、脉冲时间、处理量对杀菌率的影响差异极显著（p〈0．01）;相同杀菌条件．下超声波杀菌时间较传统的水浴热杀菌短,有利于保持食品品质。     

中国黄酒风味感官特征及其风味轮的构建

首次对中国黄酒的风味轮进行绘制,由国家黄酒评委组成的品评小组结合消费者品评小组,对6种不同类型、不同特点的典型黄酒进行风味感官品评,给出黄酒风味感官基本描述语,对描述语进行筛选整理后,参照啤酒、葡萄酒及清酒风味轮,对描述语进行归类,绘制出中国黄酒风味轮。从黄酒风味轮描述语中,运用多元统计方法及ISO 11035感官描述语选择方法的国际标准,选择确定重要的、而且具有典型差异性的味觉和嗅觉描述语：甜味、苦味、涩味、酸味、鲜味、醇香、焦糖香、果香、药香、烟气香、曲香及蜂蜜香12个作为构成黄酒风味轮廓的主要描述语。这些描述语分别经由国家黄酒评委和消费者应用于黄酒描述分析,表明可以表征中国黄酒主要的基本风味感官特征,可用于黄酒基本描述性感官分析。     

甜橙果肉粉对橙油风味物质的吸附性能研究

为探究柑橘果肉在风味吸附方面的机制,测定了甜橙果肉粉的成分构成、氮气吸附-脱附等温线,采用扫描电子显微镜（scanning electron microscope, SEM）观察了其微观结构,采用气相色谱-质谱法（gas chromatography-mass spectrometry, GC-MS）测试分析了其对橙油风味物质的吸附性能。成分分析结果表明甜橙果肉粉主要由膳食纤维（51.87%±3.12%）、蛋白质（20.47%±0.58%）、脂肪（11.33%±1.60%）、淀粉（4.06%±0.59%）构成。SEM观察结果及氮气吸附-脱附等温线分析结果表明,甜橙果肉粉复合物中存在丰富的褶皱和缝隙等不规则结构,比表面积达2.98 m2/g。GC-MS测试分析结果表明,甜橙果肉粉对橙油典型香气成分例如柠檬烯、γ-萜品烯、β-月桂烯、β-水芹烯、芳樟醇、辛醛、壬醛等有明显的吸附作用,尤其与直链脂肪醛、含氧萜类衍生物的相互作用较明显,而对α-蒎烯、桧烯等双环单萜类成分的吸附作用相对较弱。综上,甜橙果肉粉中各组成成分交联而成的褶皱和缝隙结构是其发挥风味吸附作用的重要基础,研究结果可为进一步开发利用甜橙果肉提供参考。     

Orange Flavor Absorption Into Various Polymeric Packaging Materials

Citrus oil components (from cold-pressed and terpeneless oils), which contribute substantially to flavor of orange juice, were shown to be absorbed into various polymeric materials [low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), and surlyn (S)] used in aseptic packaging. Equilibration of absorption took place within 4 days, while extraction of the oil constituents occurred in 24 hr when higher temperatures were used. Substantial absorption of oil constituents by LDPE and S occurred while highly crystalline polymers (PP and HDPE) did not absorb much. The degree of absorption also depended on the nature of the oil constituents. Absorption was higher for terpene constituents followed by sesquiterpenes and aldehydes. Swelling factors showed that highly crystalline polymers (HDPE and PP) swelled less than crystalline polymeric materials. Citrus oil affected the crystallinity of the polymers by lowering their melting point and percent crystallinity.     

Physical/Chemical Nature of Pectin Associated with Commercial Orange Juice Cloud

The cloud pectin content of two commercial orange juice concentrates was 4.7 and 4.3%. The cloud pectin was solubilized to varying degrees in 6% citric acid. pH 2.5; in 10M urea-6% citric acid, pH 2.5; by hydrolysis of cloud protein with protease; and in sodium oxalate; pH 4.5. Much of the urea-solubilized pectin reprecipitated upon dialysis. The binding of orange cloud to amino paramagnetic latex particles demonstrated a clear association of cloud pectin with cloud protein. Simulation of orange juice processing conditions indicated that some of the cloud pectin arises from the pulp during processing. About 60% of the cloud pectin is soluble pectin that has become associated with cloud protein, 25–30% is calcium pectate and 15% is protopectin.     

桔汁酿酒可行性研究

对以无核桔为原料生产桔子酒的可行性进行了研究。探讨了温度、时间、接种量等因素对酒体品质及风味的影响,并通过感官评定得出桔子酒的最佳生产工艺。结果表明：采用压榨取汁,主酵温度 23℃、酵母接种量 2× 106cfu/mL、主酵时间 5d、后酵温度 10℃、时间为 21d,所酿制的桔子酒果香浓郁、风味独特。     

Effect of Thermal Processing and Carbon Dioxide-assisted High-pressure Processing on Pectinmethylesterase and Chemical Changes in Orange Juice

ABSTRACT: The effects of high-pressure processing (HPP), CO₂-assisted high-pressure processing (HPP + CO₂), and thermal processing on the chemical and physical properties of single-strength Valencia orange juice were evaluated over 4 mo of storage at 4 and 30 °C. The HPP + CO₂ juice had the greatest cloud stability and highest ascorbic acid retention. Volatile compound losses were lowest in the HPP juice and lower in the HPP + CO₂ juice compared to the thermally processed juice (p < 0.05). HPP + CO₂ produced a cloud-stable orange juice with more ascorbic acid and flavor volatiles than thermally processed juice (p < 0.05).     

中国酿造食醋风味轮的构建及应用

利用建立的食醋感官评价小组,对中国主要的酿造食醋进行了风味评价。首次构建了中国酿造食醋的风味轮,其中包括16个类别共45个描述词。运用方差分析、主成分分析等方法筛选出了16个能够描述中国酿造食醋风味差异的词汇,其中味觉描述词包括酸味、甜味、鲜味、咸味、涩味、苦味6个,嗅觉描述词包括酸气、甜香、焦香、酱香、果香、麸皮香、烟熏香、米香、酒香、花香10个。对选择的酿造食醋样品进行感官描述性分析,发现不同类型的酿造食醋风味有明显差异。     

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...     

Kinetic Models for Thermal Inactivation of Multiple Pectinesterases in Citrus Juices

First-order kinetic model of a two-component system was applied to investigate heat inactivation of multiple pectinesterases in citrus juices. The conventional log-linear model was applied to determine D- and z-values of thermolabile and thermostable pectinesterases in citrus juices, respectively, for use in the two-component model. A parameter for concentration of enzyme populations in the juice was included in the model. The two-component model predicted results were in better agreement with the observed heat pasteurization curves than those predicted by the log-linear kinetic model. The two-component model is especially useful for optimizing temperature-time conditions for pasteurizing citrus juices.