Concentration of Phenolic Compounds Change in Storage Brines of Ripe Olives

The effects of cultivar, salt concentration and temperature on changes in phenolic compounds during storage of ripe olives were studied, using a 2³ factorial design. The effect of salt was negligible. Higher temperature increased phenols diffusion rate into brines for two cultivars assayed. The cultivars, Hojiblanca and Cacereña varied in poly-phenol content. Throughout storage there was hydrolysis of glucosides intially in flesh (oleuropein, verbascoside and luteolin 7-glucoside due to the acidic conditions. This effect caused the content of oleuropein in brines to always be lower than 1.5 mM and resulted in a continous increase in level of hydroxytyrosol     

Ripe Olives Storage Liquids Reuse During The Oxidation Process

Storage of ripe olives in liquids with high acetic acid content under anaerobic conditions led to glucose accumulation, low ethanol, and high chemical oxygen demand (COD). In contrast, low acid concentrations and anaerobic conditions produced a high level of ethanol and slightly lower COD while aerobic conditions produced low glucose, ethanol and COD. Surface color of ripe olives improved when storage liquids were used in the second washing of the darkening step. Firmness also increased with increasing proportion of storage liquids reuse, although olives from highly acidic media were softer than those stored in low acid media.     

食品包装用复合膜、袋的卫生性能分析与改进措施

食品包装是食品重要的组成部分,绿色包装是我国食品软包装的发展趋势。针对我国复合膜袋卫生指标存在的问题,从原料、生产工艺、国家标准等方面分析了产品产生不合格的原因。研究我国相关塑料产品的法律和规定,并提出学习和借鉴美国、欧盟、日本等国的相关法律法规,从政府、企业和公众3个层面出发,共同提高复合膜袋质量的方案,文中也探讨了我国复合膜袋的发展趋势。     

The Influence of pH and Sodium Hydroxide Exposure Time on Glucosamine and Acrylamide Levels in California‐Style Black Ripe Olives

Acrylic acid, N‐acetyl‐glucosamine and glucosamine were investigated for their role in the formation of acrylamide in California‐style black ripe olives [CBROs]. Levels of acrylic acid and glucosamine are reported for the first time in fresh (333.50 ± 21.88 and 243.59 ± 10.06 nmol/g, respectively) and in brine‐stored olives (184.50 ± 6.02 and 165.88 ± 11.51 nmol/g, respectively). Acrylamide levels significantly increased when acrylic acid (35.2%), N‐acetyl‐glucosamine (29.9%), and glucosamine (124.0%) were added to olives prior to sterilization. However, isotope studies indicate these compounds do not contribute carbon and/or nitrogen atoms to acrylamide. The base‐catalyzed degradation of glucosamine is demonstrated in olive pulp and a strong correlation (r² = 0.9513) between glucosamine in olives before sterilization and acrylamide formed in processed CBROs is observed. Treatment with sodium hydroxide (pH > 12) significantly reduces acrylamide levels over 1 to 5 d without impacting olive fruit texture.     

高效液相色谱法检测橄榄果酒中的Vc和糖类物质

本文建立了HPLC法同时测定橄榄果酒样品中维生素C、果糖、葡萄糖、麦芽糖和蔗糖的方法.对橄榄果酒进行前处理,以Waters High Performance Carbohydrate Column 60A 4.6x250 mmx4μm HPLC色谱柱为固定相,乙腈-水(90:10)为流动相,蒸发光散射仪( ELSD)为...     

Controlled Fermentation of Spanish-type Green Olives

Pure culture fermentation of Spanish-type green olives was developed. The method used no heat treatment, included chlorination of both fermentor and olives, used sterile lye, water and brine, and acidification with lactic acid before inoculation. Lactobacillus pluntarum was used as test species. After 34 days fermentation, citric acid, mannitol and malic acid were completely degraded and ～ 90% of available glucose and fructose, but <30% sucrose, were utilized. Fermentation products were D- and L-lactic acid, ethanol, succinic, and acetic acid with a calculated carbon recovety of 107.5%. D-lactic predominaied over L-lactic acid. No differences were found between flavor of pure culture and naturally fermented olives, but there was a tendency towards preference of the latter.     

Cell Wall Composition of Olives

Cell walls of olives (Olea europaea L.), Hojiblanca and Manzanilla, were isolated and fractionated into polysaccharides, and compositions compared. Pectic and hemicellulosic fractions were purified by ion exchange and gel filtration chromatography, and neutral sugar and uronic acid composition determined. Differences occurred between cultivars and seasons: Manzanilla had higher pectic polysaccharides and lower xylans. Hojiblanca showed similar but lesser differences. Arabinans were the main neutral pectic polysaccharides with arabinose > 80%. Homogalacturonans and rhamnogalacturonans were > 50% of the acidic pectic fractions. Degree of esterification and molecular weights were related to extracting solvent. Xyloglucans and galactoglucomannans were neutral hemicelluloses with molecular weights ? 260 kD. Glucuronoarabinoxylans had higher molecular weights (up to 400 kD). Acidic xylans were important in the pulp.     

Shelf Life Evaluation of Cling Peaches in Retort Pouches

Retort pouch sliced peaches in syrup were developed to replace freeze-dried peaches in a military field ration. Two processing variables were investigated: fruit source (fresh and frozen) and syrup pH (3.85 and 3.25). Peaches were stored at 4°, 21° and 38° C and evaluated periodically by sensory panels and biochemical and instrumental analyses. pH had most effect on sensory color, texture and acceptability and instrumental color and sugar composition. High positive correlations existed between a factor (consisting of five sensory quality attributes) and sensory color and texture, Hunter L and a values and sucrose level. Frozen and fresh source peaches at pH 3.85 met shelflife requirements at 21 and 38°.     

Shelf Life Evaluation of Bartlett Pears in Retort Pouches

Retort pouch pears in syrup were developed for a military ration. Processing variables were: syrup pH (4.0 and 3.5) and processing temperature (88°C and 96°C). Periodic sensory and biochemical/instrumental analyses were conducted during storage at 4, 21 and 38°C. pH had the most effect on quality measures. Bivariate correlations from Partial Least Squares (PLS) analysis indicated high positive relationships between the first PLS factor and sensory and analytical determinations: color quality, overall quality, pear flavor intensity, Hunter L, ascorbic acid and sucrose. Pears at pH 4.0, processed at either temperature, met minimum military shelf life requirements at 21° or 38°C.     

软包装自立袋在食品行业中的应用和发展

对软包装自立袋进行简述,包括其在饮料包装、工艺、生产过程中的作用。本文综述了软包装自立袋结构功能,以及在饮料包装行业中的应用现状。并对软包装自立袋在食品行业的应用前景进行了展望,为软包装自立袋有效利用提供参考。     

Heating Rate, Lethality and Cold Spot Location in Air-entrapped Retort Pouches during Over-pressure Processing

The effects of entrapped air on the heating rate, lethality and cold spot in bricks packaged in retort pouches were determined using silicone rubber bricks (10 × 14.5 × 2cm), with 5 thermocouples positioned from the geometric center-point to near the top surface. The packaged bricks were processed in steam/air media at two temperatures (121.1°C and 115.6°C) and two levels of superimposed air overpressure (corresponding to 65% and 75% steam). With the exception of the highest level of over-pressure, (121.1°C, 65% steam content), entrapped air volumes >20 mL reduced heating rates and lethality, and shifted the cold spot from the geometric center. At 60 mL of entrapped air the point of least lethality was near the brick surface.     

机械损伤对橄榄采后品质及其生理的影响

通过人工上树采摘、拦网采摘和自然掉果三种采收方式,探讨不同程度的机械损伤对橄榄采后商业品质及其生理的影响,结果表明:橄榄果实受到机械损伤后,在贮藏期间,果实的失重率和可溶性固形物呈线性增加,细胞膜透性增大,有机酸和VC的含量减少,含水量快速下降,呼吸速率迅速提高,PPO、POD、CAT活性上升,加速了果实的衰老进程.轻采轻放,减少机械损伤,对延长橄榄果实贮藏寿命,提高果品商业品质具有积极意义.     

Color and Texture Change Kinetics in Ripening Bananas

Kinetics of color and texture changes in ripening bananas were investigated as a function of storage temperature (10, 16, 22, 28 °C). Color was evaluated in terms of L, a and b values as well as the total color difference (ΔE) representing the residual deviations from the ripe stage. Puncture force (PF) was used to evaluate the texture properties of banana. The results indicated that the time dependence of L, ΔE and PF values followed a logistic model, while a and b values were well described by a simple zero-order and fraction conversion models, respectively. The Arrhenius equation adequately described the temperature dependence of the reaction rate constants for both color and texture parameters, from which the activation energies and rate constant at reference temperature 15 °C were obtained. There were significant linear correlations between color parameters (L, a, b, ΔE) and texture parameter (PF).     

Selection of Yeasts as Starter Cultures for Table Olives

Ninety‐nine yeasts were isolated from Bella di Cerignola table olives; first, the strains were studied in relation to their ability to produce biogenic amines in a laboratory medium and 49 strains were positive to this assay and cut off from the research. The remaining 50 strains were characterized for their enzymatic traits (β‐glucosidase, catalase, pectolytic, xylanolytic, and lipolytic activities) and for their ability to grow at different temperatures, pHs, with salt or lactic/acetic acids added. Data were used for the evaluation of growth index and submitted to cluster and principal component analyses to choose the most promising 4 strains. In the final step of the research, the strains were inoculated as a cocktail in a model brine, containing different amounts of salt (4% to 12%) and glucose (0% to 3%), and adjusted to different pHs (4.0 to 9.0). Data analysis through a multiple regression procedure highlighted that salt, glucose, and pH acted in a different way within the storage and NaCl affected yeast growth only for few days, and then glucose and pH played a major role. Practical Application Olive fermentation relies upon a complex microflora, including lactic acid bacteria and yeasts; the selection of suitable strains of yeasts intended as starter cultures, as well as their inoculation in brines, could improve the fermentation.     

Gluconic Acid Influences Texture and Color of Canned Asparagus

The color and texture of canned asparagus spears were measured using a shear-press and a Gardner color difference meter. Canning spears with 1% gluconic acid reduced pH of asparagus tissue to = 4.1 within 24 hr. After 5 mo storage, the 1% acidified pasteurized spears were lighter, less green, and more yellow than nonacidified retorted spears. Acidification with a milder thermal process almost doubled firmness of the acidified spears.     

Vitamin Retention, Color and Texture in Thermally Processed Green Beans and Royal Ann Cherries Packed in Pouches and Cans

Thiamin (B-1) ascorbic acid (AA) and vitamin B-6 (B-6) were determined in pouched and canned green beans immediately after processing and after storage at 24–26°C or 38°C. AA and B-6 were also determined in pouched and canned cherries before and after storage at 24–26°C. There was significantly more B-1 and AA in drained pouched green beans, and more AA in drained pouched cherries than in canned ones. B-6 values in the solids of the pouched and canned products were not significantly different. These three vitamins were significantly reduced in drained pouched and canned green beans after storage at 38°C. B-6 was significantly reduced in the stored cherries. Compared to canned, the pouched products were brighter and firmer in texture.