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.     

不同类型橙汁挥发性风味成分的测定与比较

为分析甜橙品种及加工方式对橙汁挥发性风味成分的影响,采用固相微萃取结合气-质联机(SPME-GC-MS)对4个品种的鲜榨汁、5个品种的自制非浓缩还原型橙汁(NFC)以及两种商业橙汁(NFC橙汁和浓缩还原汁)共11个样品的挥发性风味成分进行了分析,共鉴定出73种成分,其中9种酯类、14种醇类、4种酮类、8种醛类、34种萜烯类碳氢化合物、3种烷以及叔丁基羟基苯(BHT).丁酸乙酯、α-蒎烯、柠檬烯、里那醇、4-萜烯醇、顺-香芹醇、香芹酮、紫苏醛、α-人参烯、巴伦西亚橘烯在各类样品中均有检出,它们是橙汁的特征挥发性成分.不同橙汁的挥发性风味成分组成存在一定的差异,并且与甜橙品种以及加工工艺有关.本研究结果将为不同类型橙汁的鉴别以及质量控制提供参考.     

Effect of Storage Temperature on the Stability of Aseptically Packaged Concentrated Orange Juice and Concentrated Orange Drink

Commercial orange drink concentrate and two orange juice concentrates were aseptically packed in flexible bags and stored at 4°, 15°, 22°, and 30°C for 6 months. Ascorbic acid, nonenzymatic browning and sensory quality were measured monthly. Sensory characteristics for drink concentrate deteriorated after 3 and 4 months at 30°C and 22°C, respectively. Juice concentrates were unacceptable after 2 and 5 months at 30°C and 22°C, respectively. Drink concentrate ascorbic acid loss was greater than juice concentrates at 4°, 15°, and 22°C. Changes in nonenzymatic browning as measured by Hunter color and by absorbance at 420 nm were similar to changes in other containers. The quality of refrigerated aseptic drink (15°C) and juice (4°C) was similar to frozen concentrates (?18°C).     

Nonenzymatic Browning in Aseptically Packaged Orange Juice and Orange Drinks. Effect of Amino Acids, Deaeration, and Anaerobic Storage

Single strength orange juice and synthetic orange drinks containing 10% (v/v) orange juice and 0.4 and 0.8% w/w concentrations of each amino acid, aspartic acid, arginine, and 4-aminobutyric acid were aseptically packaged using 250 mL Tetra Brik Packs. Samples were stored at 24°C for 16 wk under anaerobic and aerobic conditions, and were tested every 4 wk for nonenzymatic browning, ascorbic acid (AA) retention, dehydroascorbic acid (DHAA) formation, and sensory changes. Deaeration and anaerobic storage resulted in increased retention of ascorbic acid. However, there was very little change in the flavor score, browning, color or change in the amino acid content of the different samples during the entire storage period.     

Quality Parameters of Packaged Refrigerated Apple Cubes in Orange Juice

The quality of apple cubes (Red Delicious and Granny Smith) maintained in pasteurised or fresh orange juice with sucrose and chemical preservatives: acidulants (citric and ascorbic acids) and potassium sorbate or sodium benzoate, packaged in plastic films of different gaseous permeability (polyethylene (PE) and EVA-SARAN-EVA (ESE)), was analysed during storage at 10 °C. Surface colour, microbial growth and instrumental texture changes were measured. Microbial flora was identified, and its growth was mathematically modelled. Shelf-life values of 10d in polyethylene and higher than 25d in ESE film, maintaining acceptable quality attributes, were obtained for both apple varieties in pasteurised juices. For Red Delicious in unpasteurised orange juice with acidulants and potassium sorbate (0.125-0.250 g/kg), shelf-life values were 7.5-8.5d in PE and higher than 15 d in ESE film. For Granny Smith apples in unpasteurised juice without potassium sorbate, shelf-life values were 10 d in PE and higher than 15 d in ESE. Higher concentrations (0.375-0.50 g/kg) of potassium sorbate adversely affected colour. Sodium benzoate was discarded as preservative because it produced severe browning in both apple varieties. All the samples showed safe sanitary conditions; coliforms microorganisms did not grow in any of the tested conditions.     

Sensory Attributes and Volatile Components of Stored Strawberry Juice

Juices from three strawberry cultivars were stored at 2°C and 25°C for 6 wk and evaluated for the sensory attributes fresh strawberry, strawberry-jam, off-flavor, green, and sweet. Fresh flavor declined while off-flavor increased during storage, with the largest changes occurring at 25°C. Juice color and ascorbic acid also degraded much faster at 25°C. Fifteen volatiles were measured using headspace solid phase microextraction and gas chromatography. 2,5-dimethyl-4-hydroxy-3(2H)-furanone and 2,5-dimethyl-4-methoxy-3(2H)-furanone were positively related to fresh flavor and negatively related to off-flavor, while -terpineol was inversely related to fresh flavor. These volatiles explained almost 90% of the variation for fresh and off-flavor attributes.     

Nonenzymatic Browning in Aseptically Packaged Orange Drinks: Effect of Ascorbic Acid, Amino Acids and Oxygen

Nonenzymatic browning of single strength orange juice and synthetic orange drinks containing 10% (v/v) orange juice has been studied under aerobic and anaerobic conditions. The juice and drinks were aseptically packaged into two types of flexible film (retort pouch and polyethylene Whirl-Park) and stored at 20 wk at 24°C. Ascorbic acid retention was affected by the processing itself, the concentration of added amino acids, and by the packaging material. The effect of amino acids on browning was found to be linear with concentration and was more pronounced in the presence of high levels of ascorbic acid.     

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.     

锦橙和宫川果汁香气成分比较研究

采用同时蒸馏提取法(SDE)制备样品,GC-MS联机分析,计算机谱图库检索定性,对锦橙和宫川蜜柑果汁的香气成分进行了鉴定,共检测出73种香气化合物。酯类、醇类、醛类、烯类和酮类物质是其主要香气成分,其中锦橙果汁中检出香气成分62种,宫川蜜柑果汁中检出香气成分32种。锦橙和宫川蜜柑果汁香气成分的种类和含量差别明显,因此在柑橘果汁的生产过程中,可以考虑按照一定的比例做适度的搭配,以生产出更优质的柑橘果汁。     

胡柚汁益生菌发酵挥发性风味特征

利用筛选到的2株乳酸菌植物乳杆菌L1（Lactobacillus plantarum）和发酵乳杆菌L2（L. fermentum）对胡柚汁发酵,研究其挥发性风味成分及其变化特征。采用静态-顶空固相微萃取和气相色谱-质谱联用分析方法,测定胡柚汁经此2种乳酸菌发酵后挥发性风味物质组分和相对含量,运用主成分分析法对发酵胡柚汁样品挥发性风味成分进行分析,并采用电子鼻对乳酸菌发酵胡柚汁的香气进行检测。结果表明,胡柚汁经发酵后共鉴定出79种挥发性风味物质,其中醇类20种、烯烃类15种、烷烃类12种、酮类10种、醛类5种、酯类2种、其他类15种,挥发性风味物质分别为59、36种和35种。经乳酸菌发酵后,胡柚汁挥发性风味化合物种类均增加,并检测到了胡柚汁中未被检测到的酯类、醇类、酮类和烷烃类相对含量显著提高,醛类物质相对含量大量降低。主成分分析找出了影响4个样品特征风味组分在主成分中的差异,表明主成分分析法可实现对乳酸菌发酵胡柚汁特征风味差异性的评价。电子鼻分析表明胡柚汁经不同乳酸菌发酵后风味差异显著。研究结果揭示了胡柚汁乳酸菌饮料的风味特征并为产品质量评定等提供依据。     

臭豆腐中挥发性香成分提取与分析

为分析臭豆腐中的挥发性成分,采用固相微萃取和同时蒸馏萃取的方法对北京产老才臣臭豆腐中的挥发性成分进行提取,提取物经气相色谱-质谱联用仪分析,结合对比标准品保留时间和计算分离出的成分的保留指数。结果共鉴定出43种成分,其中,醇类15种、酸类3种、酯类8种、酮类3种、醛类2种、酚类1种、硫醚类4种、杂环类5种、芳香烃类2种,采用面积归一化法确定相对含量;两种方法中都鉴定出的挥发性成分有17种,主要为醇类、酯类、含硫化合物和杂环类;对臭豆腐香气特征贡献较大的有吲哚、二甲基二硫、二甲基三硫、二甲基四硫、2,3,5-三硫杂己烷、苯酚等。     

无菌真空包装酱羊肉特征性挥发性风味成分分析

为明确无菌真空包装酱羊肉的特征性香气,采用固相微萃取和气相色谱-质谱联用技术对无菌真空包装酱羊肉进行挥发性成分分析,并结合感觉阈值和相对气味活度值（relative odor activity value,ROAV）确定其特征香气物质。结果表明：无菌真空包装酱羊肉中共检出67 种挥发性物质,包括醇类14 种、醛类17 种、酸类8 种、酮类7 种、酯类3 种、烷烃类10 种和其他类化合物8 种;采用ROAV评价各香气成分对酱羊肉总体风味的贡献,确定出14 种关键挥发性成分,分别为正辛醇、1-辛烯-3-醇、芳樟醇、4-萜烯醇、(E)-2-壬烯醛、(E)-2-辛烯醛、苯丙醛、癸醛、庚醛、己醛、壬醛、辛醛、2-十一烷酮和6-甲基-5-庚烯-2-酮,这些物质是无菌真空包装酱羊肉香气成分的重要贡献者。     

Mathematical Modeling of Microbial Growth in Packaged Refrigerated Orange Juice Treated with Chemical Preservatives

ABSTRACT Microbial flora of refrigerated orange juice was analyzed during storage at 10 °C and the effects of the following factors were discussed: 1) the previous washing process of the orange peel, 2) the different levels of the added preservatives (citric acid, ascorbic acid, potassium sorbate, sodium benzoate), 3) the gaseous permeabilities of the packaging film. Gompertz equation was applied to model molds and yeasts growth for the different treatments and packaging conditions. The washing procedure with sodium hypochlorite extend 2–3 d the storage life of the juice (time to reach microbial counts of 10⁶ CFU/ml) in both packaging films. The use of organic acids and potassium sorbate or sodium benzoate (1.66–6.94 mM) led to storage life values > 11 d in polyethylene and > 20 d in the low gaseous permeability film, maintaining good sanitary conditions.     

Ascorbic Acid Retention in Orange Juice Stored under Simulated Consumer Home Conditions

Ascorbic acid levels in 13 types of commercially packaged orange juices and a juice drink were monitored over 5–7 days at 4.5°C as stored in the original container. Comparable samples stored in an open plastic container were monitored for comparison. In both cases the average ascorbic acid loss was about 1.5–2% per day. These simulated consumer home conditions showed that juice retained an average of 88% of the original ascorbic acid after 1 wk, and 67% after 2 wk in opened containers stored at typical home refrigerator temperatures.     

纳米膜包装真姬菇贮藏期间挥发性风味成分变化分析

研究纳米膜包装真姬菇在采后贮藏过程中挥发性风味物质的变化规律。选用一种新型聚丙烯纳米膜（0.05 mm）为包装材料,在4 ℃进行12 d的真姬菇贮藏实验,采用顶空固相微萃取和气相色谱-质谱联用技术对真姬菇的挥发性成分进行分析检测,并采用相对气味活度值法和主成分分析（principal component analysis,PCA）法,确定真姬菇的特征风味物质。通过对真姬菇挥发性成分的动态监测可知,贮藏期间共鉴定出66 种挥发性物质,包括醛类23 种、醇类22 种、酮类10 种、酯类3 种、羧酸类4 种及呋喃类4 种。真姬菇挥发性物质总含量呈现先降低后升高的趋势,在贮藏前期（0 d）含量为98 927 μg/kg,贮藏中期（6 d）含量为28 079 μg/kg,贮藏后期（12 d）含量为89 021 μg/kg。相对气味活度值分析表明：正辛醛、1-辛烯-3-酮、1-辛烯-3-醇为真姬菇的特征风味物质,2-戊基呋喃对真姬菇的风味具有重要的修饰作用;反-2-辛烯醛是影响新鲜真姬菇风味形成的关键物质;反,反-2,4-壬二烯醛、3-辛酮是真姬菇风味劣化后的关键物质。PCA表明醛类和醇类对风味的影响最大。根据挥发性成分的变化规律可以有效区分不同贮藏时期的真姬菇样品,可为实现真姬菇品质的快速检测、风味鉴定以及货架期的预测提供一定的理论依据。     

Volatile Flavor Sulfur and Nitrogen Constituents of Brassica rapa L.

The volatile flavor constituents of Brassica rapa L. var laciniitolia Kitamura and Brassica rapa L. subvar Hiroshimana Kitamura have been investigated by a combination of chromatographic and spectioscopic methods. These volatile oils possess a characteristic pungent odor and taste. A total of 14 sulfur and nitrogen compounds were identified positively, including 4 isothiocyanates, 3 nitriles, 2 methylthio isothiocyanates, 4 methylthio nitriles and 1 sulfide.     

银杏外种皮挥发性成分分析

采用同时蒸馏萃取和固相微萃取两种萃取技术提取银杏外种皮的挥发性成分,并采用气相色谱-质谱联用对其挥发性物质成分进行分离鉴定。结果共鉴定出29种挥发性化合物,包括酸类9种、酯类9种、酮类3种、醛类1种、醇类4种、烃类1种、杂环类化合物2种,两种萃取物中都鉴定出的挥发性成分有12种。经SDE-GC-MS分析出的相对含量较高(峰面积比>1%)的化合物有己酸(65.88%)、丁酸(21.46%)、棕榈酸(4.53%)、辛酸(1.15%);经固相微萃取-气相色谱-质谱联用分析出的相对含量较高(峰面积比>1%)的化合物有丁酸(59.96%)、己酸(25.45%)、己酸甲酯(3.90%)、丁酸甲酯(3.59%)、乙酸(1.65%)。根据分析出的挥发性成分的香气特征可知对银杏外种皮挥发性气味贡献较大的物质有丁酸、己酸、丁酸甲酯和己酸甲酯等。     

Potentiall of Ferulic Acid as a Precursor to Off-Flavors in Stored Orange Juice

The hypothesis that free ferulic acid in stored orange juice contributes to the objectional aroma of p-vinyl guaiacol (PVG) was tested. Single-strength orange juice (SSOJ) contained 185 μg/L free ferulic acid which increased to 316 μg/L after pasteurization. Commercial samples of SSOJ contained 3.7mg/L free ferulic when incubated at 35°C for 28 days; incubation at 50°C, resulted in 9.5 mg/L, while samples kept at 4°C contained 2.9 mg/L. Simultaneously, PVG content in SSOJ increased by 2-(35°C) to 3-(50°C) fold, while addition of ferulic acid accelerated formation of PVG. Inclusion of orange juice with added ferulic acid, produced a less acceptable aroma (laboratory taste panel) than juice incubated without added ferulic acid.     

Functionality and Microbial Stability of Ultrapasteurized, Aseptically Packaged Refrigerated Whole Egg

Raw, liquid whole egg was ultrapasteurized and aseptically packaged to extend the refrigerated shelf-life and maintain functional quality. Nine processes ranged from 63.7–72.2°C for 2.7 to 192.2 sec and resulted in shelf-lives ranging from 4 to >24 weeks at 4°C. Egg pasteurized by an essentially conventional process (26.2 set, 63.7°C), aseptically packaged and stored at 4°C spoiled in 4–8 weeks. Overall, little or no change was observed in the chemical (protein and solids contents, soluble protein, pH) and functional properties (performance in cakes and custards) of the ultrapasteurized, aseptically packaged, 4°C refrigerated egg compared to raw egg. Egg of acceptable quality may be produced by this process with a 3–6 months shelf-life at 4°C.     

Quality of Enzymatically Treated 72° Brix Orange Juice Stored at Refrigerated Temperatures

Fresh Valencia orange juice was treated with 0, 70, and 350 ppm of commercial pectic enzymes, concentrated to 72° Brix and stored at –7°, –1°, 7°, and 13°C for up to 6 months. The 70 ppm enzyme treatment successfully reduced initial apparent viscosity by about 25%. For the 70 ppm enzyme treated samples after 6 months storage at all four temperatures, juice cloud remained acceptable, furfural remained below the significant level, and at ?1°C, vitamin C levels were above 32 mg/100 mL. There was no significant difference in taste after 6 months storage at ?7°C between control and 70 ppm enzyme treated samples. Product quality of enzymatically treated orange concentrate stored at refrigerated temperatures was of sufficient quality to realize potential savings of 17% in storage and 30% in refrigeration.