Stable Clouding Agent from Isolated Soy Protein

In a dilute suspension the stability of soy protein particles equalled or surpassed that of orange juice prepared from concentrate during short-term storage at 4°C. Soluble soy protein produced a stable cloud only when soluble pectin was present in the incubation medium as the particles were forming. In the absence of soluble pectin the nascent soy protein particles rapidly aggregated. This soy protein based clouding agent may provide a natural and healthy alternative to oil-derived clouding agents. The stabilization of such suspended soy protein particles also provides a model system that may be comparable to orange juice cloud for stability studies.     

A clouding agent based on modified soy protein

Several food proteins, together with some naturally occurring water-soluble gums (viscosity builders) and lecithin, are evaluated as clouding agents for formulated orange drinks. The use of these three types of natural products represents a significant advantage over the present formulations in which synthetic emulsifiers and weighting agents are used.
The effects of concentration of each of the above ingredients, pH, temperature and mode of preparation are explored and related to cloud stability, droplet size distribution and the opacity of the emulsion both in concentrated and diluted formulations. A mechanism for protein adsorption onto the droplets is suggested.     

天然起云剂——海藻多糖衍生物海藻酸丙二醇酯

起云剂又名增浊剂,是一种乳化稳定剂,其作用是在溶液中起到乳化、增稠、稳定作用,使不易相融的水油溶液能够形成混合均匀的胶状分散体,可以防止出现沉淀,并能增加口感。由于海藻酸丙二醇酯含有亲水性及亲油性的基团,添加在饮料及食品中可以起到乳化和增稠的作用,是一种天然的起云剂,在运动饮料、各种果汁饮料、益生菌、乳酸菌饮料、果冻等食品中有很好的应用价值。     

Effect of sonication on orange juice quality parameters during storage

Freshly squeezed orange juice was sonicated at various amplitude levels (40%, 70%, 100%), treatment times (2, 6 and 10 min) at a constant frequency of 20 kHz. Samples were stored for periods of up to 30 days at 10 °C. The combined effect of amplitude level, treatment time and storage period on pH, ^oBrix, titratable acidity, colour values ( L* , a* , b* ), non-enzymatic browning (NEB), cloud value and ascorbic acid content were investigated. Second order polynomial models were employed to investigate the effect of independent variables. No significant differences ( P <  0.05) in ^oBrix and titratable acidity were observed. Significant changes were observed in juice pH and colour values. During storage NEB increased while both cloud value and ascorbic acid content decreased. Predictive models developed for colour values, cloud value, NEB and ascorbic acid content were highly significant and were closely correlated to experimental data. Degradation mechanisms are proposed for the key quality parameters.     

Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice. Part I: Impact on overall quality attributes

Mild heat pasteurization, high pressure processing (HP) and pulsed electric field (PEF) processing of freshly squeezed orange juice were comparatively evaluated examining their impact on microbial load and quality parameters immediately after processing and during two months of storage. Microbial counts for treated juices were reduced beyond detectable levels immediately after processing and up to 2 months of refrigerated storage. Quality parameters such as pH, dry matter content and brix were not significantly different when comparing juices immediately after treatment and were, for all treatments, constant during storage time. Quality parameters related to pectinmethylesterase (PME) inactivation, like cloud stability and viscosity, were dependent on the specific treatments that were applied. Mild heat pasteurization was found to result in the most stable orange juice. Results for HP are nearly comparable to PEF except on cloud degradation, where a lower degradation rate was found for HP. For PEF, residual enzyme activity was clearly responsible for changes in viscosity and cloud stability during storage.

Industrial relevance

Development of mild processing technologies with a minimal impact on fruit juice can be considered as a true alternative of fresh fruit. The present work presents a fair comparison of mild heat treated, high pressure (HP) and pulsed electric field (PEF) processed orange juice as an alternative for thermal pasteurization. Orange juices were monitored during two months of storage.     

Colour and label evaluation of commercial pasteurised red juices and related drinks

Despite growing demand by consumers for healthy beverages, artificial colours are still widely used. Levels of anthocyanins and artificial colours were determined by HPLC with UV-Vis detection in red orange juices and other red beverages (nectar, juice-based, health, carbonated and sports drinks). The contribution of pigments to the visible colour of the beverage was calculated. Red orange juice samples contained about 34?mg?l^?1 of anthocyanins, which were responsible for about 92% of the visible colour. Red juice-based drinks, containing from 0% to 30% of red orange, berry, grape or pomegranate juices, had low levels of anthocyanins (about 7?mg?l^?1) and high levels of E129 (about 32?mg?l^?1), which were responsible for about 90.7% of the colour of these beverages. Red health drinks, enriched with vitamins and polyphenols, contained from 3% to 50% of red fruit juices. Also in this case the E129 levels were higher (about 22?mg?l^?1) than anthocyanins (about 9?mg?l^?1), and were responsible for the colour of the beverages (76.1%). High levels of artificial colours were found in red orange carbonated drinks, but in comparable amounts with those found in the other beverage samples, while anthocyanins were only present in trace amounts. Although all of the beverages claimed to contain red fruits on the labels, no correlation was found between the level of anthocyanins and the declared percentage of red fruits. These labels generally conformed with the requirements of the law, but food product labels can often be misleading to consumers about the real characteristics of the product.     

High-Pressure Processing of Orange Juice: Combination Treatments and a Shelf Life Study

ABSTRACT: Several process alternatives for the stabilization of fresh orange juice at pressures between 500 MPa and 800 MPa and temperatures between 25 and 50 °C were evaluated. Processing at 800 MPa and 25 °C for 1 min and use of thermally pasteurized pulp yielded the lowest level of residual pectinmethylesterase activity (3.9%) and good cloud stability at 4 and 37 °C over a period of more than 2 mo. Ascorbic acid loss was less than 20% after storage for 3 mo at 4 °C or 2 mo at 15 °C. Color values were stable during storage at 4, 15, and 26 °C     

Clarification of Citrus Juice is Influenced by Specific Activity of Thermolabile Pectinmethylesterase and Inactive PME-Pectin Complexes

ABSTRACT: Thermolabile pectinmethylesterase (PME) from Valencia orange pulp was extracted, partially purified by cation exchange chromatography (IEX), and added to reconstituted orange juice at 2 units/ml. Of the juices that clarified, %T increased, cloud particle size increased and % degree of esterification (DE) decreased in the 15 d storage study. The rate of clarification was most rapid for juices with added PME extracts that never bound Hi-Trap SP and contained 36 and 27 kDa peptide, intermediate for crude extracts of PME not applied to IEX, and lowest for PME extracts that bound Hi-Trap SP and contained 36 and 13 kDa peptide. These results suggest that PME-pectin complexes and low peptides moderate PME activity and juice clarification.     

Effect of clouding agents on the quality of apple juice during storage

Apple pomace, (AP) was subjected to evaluation as potential source of clouding and antiradical agent in cloudy apple juice (CAJ). The evaluation was carried out in comparison with three hydrocolloids, namely sodium carboxymethyl cellulose (CMC), xanthan (XA), and pectin (P). The quality parameters of cloudy apple juice such as cloud stability, viscosity, phenolic content, sensory evaluation and antioxidant activity had been studied since these parameters control the consumer acceptance of that product. All the analyses were carried out for fresh and treated juices after storage at 4 and 25 °C for two weeks. The cloud stability of juices added decreased quickly and remained more stable than the untreated treatment. However, the hydrocolloids showed significant (P < 0.05) increase in viscosity, they exhibited deterioration in sensory attributes. The results indicated a good correlation between phenolic degradation and the radical scavenging activities.     

A natural clouding agent from orange peels obtained using polygalacturonase and cellulase

Clouding agents (CAs) provide high cloud stability when they are diluted and added to fruit beverages. Natural CA could also give the visual appearance and sensorial aspect of a natural cloudy fruit juice beverage. In addition, natural CAs are preferred over the synthetic ones by consumers. Therefore, the main objective of this study was to obtain a natural CA from orange peel that provided high cloud stability of fruit beverages. The treatment included the use of polygalacturonase (PG) and cellulase (C) to hydrolyze most of the peel components. Orange peels treated with 69 mg/kg of C and 90 μl/kg of PG during 80 min at 48 °C led to a CA that provided a cloudy stable solution on a fruit beverage. This CA presented a cloud stability of 94.7 days that represented a turbidity reduction of 9.1% after 9 days under fridge temperatures. Otherwise, the treatment conditions to get the highest cloud stability were not coincident to those necessary to preserve the color or to obtain the greatest extraction yield of the CA.     

橙汁混浊的稳定性

研究成熟度、制汁工艺、酶处理、贮藏条件对橙汁混浊稳定性影响。结果表明：随着成熟度增加,橙汁混浊度呈上升趋势;胶体磨细微化可以增加果浆中果胶、可溶性果胶的溶出,果胶含量显著增加(P ＜ 0.05);果胶酯酶(PE)活性影响橙汁混浊稳定性,应完全钝化;采用果胶酶酶解会破坏橙汁浑浊稳定性,木瓜蛋白酶酶解橙汁浑浊度的影响不明显;4℃和15℃贮藏对橙汁混浊度的影响不显著(P ＞ 0.05),25℃贮藏对橙汁混浊度降低影响显著(P ＜ 0.05),常温贮藏不利于保持橙汁混浊稳定性。     

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.     

Beverage cloud stability with isolated soy protein

The purpose of this study was to optimise the use of isolated soy protein (ISP) as a clouding agent for beverages. ISP was fractionated by hydrophobic interaction chromatography (HIC) using 2 M KCl in a step gradient manner. A hydrophilic and a hydrophobic fraction were collected. The proteins therein were separated by SDS-PAGe. Each fraction was combined with citrus pectin in nine different ratios at pH 3·7 and subjected to cloud stability and turbidity studies for 28 days at 4°C. The molecular weight patterns of the two fractions were different, indicating separation in the HIC column. Analysis of variance with repeated measures found no significant difference in cloud stability between the two fractions (P<0·05). Empirically, the hydrophilic fraction acted as a better clouding agent. Significant differences in cloud stability and cloud turbidity were found between different ratios of pectin: protein (P<0·05). No correlation was found between the initial cloud composition and cloud stability. Hydrophilic fraction in pectin: protein ratios 1: 2 and 4:1 gave optimum cloud stability. This study reiterated the usefulness of ISP as a clouding agent. © 1998 Society of Chemical Industry.     

Use of Banana Peel Extract To Stabilise Antioxidant Capacity and Sensory Properties of Orange Juice During Pasteurisation and Refrigerated Storage

Banana peel extract (BPE) was added to freshly squeezed orange juices (FSJ) and orange juices from concentrate (JFC), in order to evaluate if it stabilises their antioxidant activity, sensory attributes and physicochemical characteristics after heat treatment and during refrigerated storage. Mild pasteurisation increased shelf life in refrigeration for both types of orange juice, although JFC was more stable than FSJ. Antioxidant activity, determined as ABTS^?+ scavenging capacity, tends to decrease with refrigeration time. However, when BPE was added, pasteurised juices tend to have greater capacity to scavenge ABTS^?+ over time. No relevant effects were observed on the capacity to inhibit lipid peroxidation. Panellists found it extremely difficult to detect differences between juices with BPE and conventional ones. Moreover, panellists found the juices with BPE were more acceptable than conventional ones, although some modifications became more evident over time. The sensory quality of the JFC remained more stable during storage than that of FSJ. Juice colour changed slightly after heat treatment, but these changes tended to disappear over time. Adding BPE increased the total soluble solid content in all FSJ and in unpasteurised JFC. Adding BPE or pasteurising did not produce significant changes in pH in either type of juice. An increase of pH and acidity was detected in all the FSJ (except in acidity of juices without BPE) with time of refrigeration.     

Stability of enterocin AS-48 in fruit and vegetable juices

Enterocin AS-48 is a candidate bacteriocin for food biopreservation. Before addressing application of AS-48 to vegetable-based foods, the interaction between AS-48 and vegetable food components and the stability of AS-48 were studied. Enterocin AS-48 had variable interactions with fruit and vegetable juices, with complete, partial, or negligible loss of activity. For some juices, loss of activity was ameliorated by increasing the bacteriocin concentration, diluting the juice, or applying a heat pretreatment. In juices obtained from cabbage, cauliflower, lettuce, green beans, celery, and avocado, AS-48 was very stable for the first 24 to 48 h of storage under refrigeration, and decay of activity was markedly influenced by storage temperature. In fresh-made fruit juices (orange, apple, grapefruit, pear, pineapple, and kiwi) and juice mixtures, AS-48 was very stable for at least 15 days at 4 degrees C, and bacteriocin activity was still detectable after 30 days of storage. Gradual and variable loss of activity occurred in juices stored at 15 and 28 degrees C; inactivation was faster at higher temperatures. In commercial fruit juices (orange, apple, peach, and pineapple) stored at 4 degrees C, the bacteriocin was completely stable for up to 120 days, and over 60% of initial activity was still present in juices stored at 15 degrees C for the same period. Commercial fruit juices stored at 28 degrees C for 120 days retained between 31.5% (apple) and 67.71% (peach) of their initial bacteriocin activity. Solutions of AS-48 in sterile distilled water were stable (120 days at 4 to 28 degrees C). Limited loss of activity was observed after mixing AS-48 with some food-grade dyes and thickening agents. Enterocin AS-48 added to lettuce juice incubated at 15 degrees C reduced viable counts of Listeria monocytogenes CECT 4032 and Bacillus cereus LWL1 to below detection limits and markedly reduced viable counts of Staphylococcus aureus CECT 976.     

苦笋复合饮料的研制

单纯的苦笋饮料 ,其味甘苦单一 ,适口性差。把苦笋、胡萝卜、柑桔花三者配合使用 ,通过正交试验进行配方优选 ,结果表明 ,最佳风味调配浓度为 :苦笋汁 10 % 胡萝卜汁 10 % 柑桔花汁 3 % ,由此调制成的苦笋复合饮料营养丰富 ,具有独特的风味及一定的保健作用。     

The physicochemical and rheological properties of a milk drink flavoured with cajeta,a Mexican caramel jam

This research was conducted to study physicochemical and flow properties of a milk drink with the inclusion of caramel jam in relation to formulation and storage. The systems were prepared, by following a Box Behnken experimental design, including fat, gum, and flavour as variables; drinks were successfully analysed through 3 weeks of storage. Density and moisture of drinks were stable through the storage time, in contrast to acidity, colour, pH, and flow properties; the hydrocolloid content had greatest influence on rheological properties. A contour surface methodology was used to establish the corresponding relationship of three flow parameters affected by the studied variables.     

红曲橙色素的提取及其稳定性研究

以固态发酵生产的红曲色素为材料,从色素的提取方法、稳定性测试及与氨基酸反应3方面进行研究。结果表明,用板层析方法可分离、制备较纯的橙色素。该色素的热稳定性良好,光稳定性差;酸性条件下较稳定,pH>5.7时色素可能发生变化,导致吸光值下降,最大吸收峰对应波长发生位移;Na2SO3与H2O2对橙色素有一定的破坏作用,NaCl与蔗糖没有太大影响;不同氨基酸与橙色素会发生不同程度的反应,文中对谷氨酸和橙色素反应生成的衍生物进行了分析,确定出其分子量和结构。     

Opalescent and cloudy fruit juices: formation and particle stability

Cloudy fruit juices, particularly from tropical fruit, are becoming a fast-growing part of the fruit juice sector. The classification of cloud as coarse and fine clouds by centrifugation and composition of cloud from apple, pineapple, orange, guava, and lemon juice are described. Fine particulate is shown to be the true stable cloud and to contain considerable protein, carbohydrate, and lipid components. Often, tannin is present as well. The fine cloud probably arises from cell membranes and appears not to be simply cell debris. Factors relating to the stability of fruit juice cloud, including particle sizes, size distribution, and density, are described and discussed. Factors promoting stable cloud in juice are presented.     

CHARACTERIZATION OF CLOUD COMPONENTS FROM SELECTED TROPICAL FRUITS

ABSTRACT

The composition and characteristics of insoluble fruit matter (IFM) and alcohol insoluble solids (AIS) from banana, mango and orange were evaluated. The galacturonic acid content was significantly higher for mango and orange pectin (6.0%) compared to banana (5%). The degrees of esterification of pectin in AIS were 78 ± 5, 85 ± 6 and 85 ± 2 for mango, orange and banana, respectively. Proteins in the fruit pulps were of low molecular weight (<100,000 Da). The relative proportions of the amino acids in the AIS and IFM were similar, with predominant aspartic acid and low methionine and tyrosine contents. Phenolic compounds were highest in banana pulp (138 ± 2 mg gallic acid equivalent/L = mg GA/L) compared to 102 ± 8 mg GA/L for orange. Phenolic compounds were about 10‐fold less (15 ± 2 mg GA/L) in mango.

PRACTICAL APPLICATIONS

This work has applications to the development of natural clouding agents for juices, juice‐added beverages and protein‐fortified beverages. The chemical analysis provides fundamental information on the potential for stable protein interactions from banana and mango, tropical fruits that are desirable in beverages. Further, the research enhances the potential for value‐added processing of these fruits.