Impact of freeze-drying shelf temperature on the bioactive compounds,physical properties and sensory evaluation of a product based on orange juice

Freeze-drying is a good alternative means of obtaining fruit products, with a significant amount of thermolabile bioactive compounds. Despite the excellent benefits, this method provides the dehydrated product, and its main drawback is its high cost due to the duration of the process. Heat may be applied to the shelf so as to shorten the process time, as long as this does not affect the quality of the product. In this study, the impact of the freeze-drying shelf temperature, 30 and 50 °C, on the bioactive compounds of the product obtained from an orange juice formulated with gum Arabic and bamboo fibre has been considered, as has the temperature’s effect on the porosity, colour and mechanical properties of the cake and on the flowability and the rehydration capacity of the powder, together with the sensory evaluation of the rehydrated product. The results obtained point to 50 °C as being the recommended temperature for the freeze-drying of this product. This temperature shortens the process time by 64%, promotes the vitamin C content with no effect on the total phenols and carotenoids, leads to the cakes having better mechanical properties and does not affect the flowability and the rehydration behaviour of the powdered product.     

Industrial orange juice debittering: Impact on bioactive compounds and nutritional value

The impact of an industrial debittering process (DP) on nutritional and bioactive compounds in orange juice (OJ) was studied. The DP was aimed at removing bitter components in OJ by physical adsorption in a resin. The levels of bioactive compounds (carotenoids, ascorbic acid and phenolics), total antioxidant activity and the colour in the fresh orange juices (non-debittered) and in the debittered counterparts were measured. The results demonstrated that the carotenoid contents were not significantly affected by the treatment. However, the debittered orange juices showed a reduction (p < 0.001) of 26% in ascorbic acid, 32% in hydroxycinnamic acids, 28% of flavones and 41% of flavanones in comparison with the non-treated juices. The antioxidant activity of the hydrophilic fraction (HF) was significantly higher (p < 0.05) in untreated juice than in debittered juices. Some colour parameters (L^∗, a^∗ and h_ab) were also affected. Discriminant analysis revealed that the canonical function related to the levels of HF compounds allowed a 100% correct classifications of the different types of juices.     

亲水性胶体对橙汁饮料稳定性的影响

目的以30%橙汁饮料为对象,研究结冷胶、黄原胶、海藻酸钠等亲水性胶体对橙汁稳定性的影响。方法采用U8(88)均匀设计筛选出对橙汁稳定性影响最为显著的因素,再通过L9(34)正交设计进一步验证优化橙汁饮料中的胶体最佳复配方案。结果对橙汁沉淀影响最为显著的胶体是海藻酸钠、结冷胶、果胶、黄原胶,而瓜尔胶、阿拉伯胶和羧甲基纤维素钠(CMC)的影响不显著,其中结冷胶和黄原胶有利于橙汁的混浊稳定性,但是黄原胶和CMC的加入会促进橙汁的絮凝产生。海藻酸钠和结冷胶是影响橙汁稳定性的重要因素,一定用量的海藻酸钠和结冷胶复配能很好抑制产品沉淀,维持体系的混浊稳定性;黄原胶是引起产品絮凝的主要因素,适量的果胶和海藻酸钠可以防止絮凝形成。结论在海藻酸钠、结冷胶和果胶添加量分别为1.2‰、0.32‰和0.8‰时,橙汁具有最佳稳定性,产品的沉淀量最少,混浊稳定性最高,同时可最大程度防止絮凝。经过验证,在最优胶体复配条件下,其沉淀稳定性为98.52%,混浊稳定性达94.89%,产品无明显絮凝。     

Effect of pressure and time on bioactive content,PPO inactivation,physicochemical and sensory properties of aonla (Emblica officinalis) juice during hydrodynamic cavitation processing

Food Science and Biotechnology - Physical and nutritional attributes of aonla juice treated with hydrodynamic cavitation (HC) at a pressure range of 5–15 psi and time between 5 to...     

Thermal processing,storage conditions,and the composition and physical properties of orange juice

Mexican orange juice bottled without pasteurization and frozen, or orange juice that was pasteurized, bottled, and frozen or orange juice pasteurized and stored at 1°C in plastic bins was sampled monthly for eight months. Juice density, cloud, and fructose levels were all significantly (P<0.05) affected by the method of processing. Pasteurization reduced orange juice ascorbic acid concentrations. The concentrations of acetaldehyde and ethyl acetate were highest in unpasteurized juice. α-pinene, β-myrcene, limonene, α-terpineol, 1-hexanol, 3-hexen-1-ol and sabinene concentrations were highest in the unpasteurized juice.     

Effects of lupin incorporation on the physical properties and stability of bioactive constituents in muffins

Germinated Australian sweet lupin (ASL) flour (after germination for 7 days) was incorporated into muffin formulation at 0%, 2%, 4%, 6% and 8% of dried muffin weight. The effect on the physical characteristics of muffins including height, diameter, colour and texture (hardness, cohesiveness, springiness and chewiness) was measured. The stability of phenolic, phytosterol compounds and the antiradical activity of the muffins before and after baking (190 °C, 25 min) were determined. The level of incorporation of germinated ASL flour affected the volume, colour, hardness and muffin texture. Muffins incorporated with germinated ASL flour at the levels used in this research exhibited higher concentrations of total phenolic compounds, phytosterol and antiradical activity than those in control muffins. The baking process did not significantly reduce the phenolic compounds, phytosterol and antiradical activity.     

Profile and levels of bioactive amines in orange juice and orange soft drink

The levels of bioactive amines, pH, soluble solids, acidity, specific gravity, and total sugars were determined in different brands of orange products. Nine amines were detected in orange juice at mean total levels of 53.5 mg l⁻¹. There were significant differences, among orange juice brands, in the levels of spermidine, synephrine, spermine, octopamine, pH and total acidity. Five amines were detected in soft drinks with mean total levels of 3.85 mg l⁻¹. There were significant differences, among orange soft drink brands, in the levels of most amines and the physicochemical characteristics. The predominant amine was putrescine, followed by synephrine and spermidine, in both orange juices and soft drinks. The levels of these amines in the soft drink varied from 5.0% to 7.6% of the mean levels in orange juice, suggesting that less than 10% of orange juice could have been used in the soft drink.     

Ohmic heating treatment for Gac aril oil extraction: Effects on extraction efficiency,physical properties and some bioactive compounds

The effects of ohmic heating on Gac aril oil extraction in comparison with conventional heating were studied. The experiments were conducted using three extraction stages with the selected ratio of Gac aril powder to n-hexane (solvent) and time for each stage of 1:7 (7 h), 1:6 (6 h) and 1:5 (5 h), respectively. The aims were to (1) study the possibility of applying ohmic method in Gac aril oil extraction and (2) compare between oil extraction using ohmic and conventional treatments. It appeared that the electrical conductivities of fresh Gac aril, Gac aril powder with water and Gac aril powder with hexane ranged between 0.54 and 1.16, 0.50–1.46 and 0.18–0.31 S·m^− 1 respectively. The extraction efficiency, color characteristics and the contents of β-carotene and lycopene of Gac aril oil were enhanced by extraction with ohmic method. Three extraction stages with ohmic heating treatment at 50 °C in all stages resulted in the highest extraction efficiency (81.40%). The SEM micrographs proved that the cell wall of the Gac aril powder after extraction with ohmic heating was more ruptured than that of conventional heating. Physical properties of Gac aril powder and residues collected from different extraction methods were diverse due to their dissimilar compositions and structures.     

橙汁混浊稳定性的研究进展

橙子榨汁后,果肉颗粒、细胞壁碎片、橙油微滴、橙皮苷结晶、细胞色素及一些无定形物质不均匀的分散于水中,使橙汁呈现特殊的不透明或混浊状态,即\     

Calcium and pH influence on orange juice cloud stability

BACKGROUND: Clarification of citrus juice is a severe quality defect related to pectin methylesterase (PME) activity. PME activity and calcium chelation of pectic acid as well as other physical interactions of cloud components influence cloud stability. The cloud stability and physical properties of pulp‐free, fresh juice with and without ammonium oxalate (AO) at pH 4.0 and pH 5.5 was evaluated. RESULTS: The only juice to clarify in the 3‐week study was the sample without AO at pH 4.0. Particle size analysis showed that the samples at pH 4.0 were larger than those at pH 5.5, and samples at pH 5.5 had a more negative zeta potential than samples at pH 4.0. Furthermore, cloud particle size increased and then decreased prior to the onset of clarification. CONCLUSION: Ammonium oxalate prevented sedimentation via calcium pectate cross‐bridges and subsequent clarification. Interaction of cloud constituents, change in particle size with pH and change in particle size with storage time suggest that, in addition to electrostatic attraction and calcium binding, cloud particles associate and dissociate via non‐covalent, non‐electrostatic interactions. Copyright © 2010 Society of Chemical Industry     

A new integrated membrane process for the production of concentrated blood orange juice: Effect on bioactive compounds and antioxidant activity

The production of high quality concentrated blood orange juice according to a new integrated membrane process, alternative to thermal evaporation, was evaluated in terms of preservation of the total antioxidant activity and of the bioactive antioxidant components of the juice (ascorbic acid, anthocyanins, hydroxycinnamic acids, flavanones). The process was based on the initial clarification of freshly squeezed juice by ultrafiltration (UF); the clarified juice was successively concentrated by two consecutive processes: first reverse osmosis (RO), used as a pre-concentration technique (up to 25–30 °Bx), then osmotic distillation (OD), up to a final concentration of about 60 °Bx. During the concentration process of the liquid fractions, a slight decrease of total antioxidant activity (TAA) was observed (−15%), which was due to the partial degradation of ascorbic acid (ca. −15%) and anthocyanins (ca. −20%). Nevertheless, this degradation was lower than that observed with thermally concentrated juice: TAA, −26%; ascorbic acid, −30%, anthocyanins, −36%. The possibility to operate at room temperature allowed reduction in thermal damage and energy consumption. On the basis of these results, the integrated membrane process may be proposed as a valuable alternative to obtain high quality concentrated juice, as the final product still showed a very high antioxidant activity and a very high amount of natural bioactive components, showing a brilliant red colour and a pleasant aroma, characteristics that were significantly lost during traditional thermal evaporation.     

Effect of thermosonication on bioactive compounds in watermelon juice

Freshly squeezed watermelon juice was subjected to thermosonication treatments with processing variables of temperature (25-45 °C), amplitude level (24.1-60 ??m) and processing time (2-10 min) at a constant frequency of 20 kHz and pulse durations of 5 s on and 5 s off. Hunter color values (L*, a* and b*), lycopene (LC), phenolic content (TP) and ascorbic acid (AA) content were measured. Higher retention of AA and LC was observed at low treatment conditions. AA, LC & TP decreased significantly at higher amplitude levels and at the maximum processing time. A second order response function covering the range of experimental conditions investigated was obtained for each of the compounds measured. Model predictions for color parameters and bioactive compounds were closely correlated to the experimental results obtained. Prediction models were found to be significant (p < 0.05) with low standard errors and high coefficients of determination (R²). It was concluded that thermosonication significantly influences key watermelon juice quality parameters     

Effects of pulsed thermosonication treatment on fungal growth and bioactive compounds of Berberis vulgaris juice

In this study, the single and combined effects of pulsed‐ultrasound amplitude (100 W, 30 kHz with 25 and 50% amplitude levels for up to 30 min) and temperature (65 °C and 75 °C) on fungal growth, total phenolics, flavonoids and antioxidant activity of Berberis vulgaris juice were investigated. The combination of pulsed ultrasound at 50% amplitude for 30 min at temperature of 75 °C as the most effective treatment was resulted in a reduction of about?3.083 ± 0.02, ?3.04 ± 0.03, ?3.10 ± 0.01 and ?2.88 ± 0.02 log (N/N₀) on S. cerevisiae, A. flavus, A. versicolor and B. fulva, respectively. Additionally, the highest total phenolics, flavonoids and antioxidant activity were noted for the barberry juice after 30 min of sonication with 50% pulsed‐ultrasound amplitude at either 65 °C or 75 °C. Pulsed thermosonication is a promising technology to extend the shelf life of B. vulgaris fruit juice because of the improvement of antioxidant activity as well as microbial quality.     

Industrial orange juice debittering: effect on volatile compounds and overall quality attributes

This study was aimed to analyse the impact of the debittering process (DP) in the overall sensory properties of orange juice (OJ) (Citrus sinensis L. Var. Salustiana). The fresh industrial squeezed orange juice (FOJ) and the corresponding OJ after the DP (DOJ) were taken. No significant differences were found in acidity, pH and total soluble solids. Colour was evaluated by image analysis (DigiEye System). Hue and lightness were lower (more reddish and darker) after debittering (P < 0.001). Odour profile (limonene, α‐pinene, ethyl butanoate, octanal, linalool, citral and terpineol) decreased significantly (from 16% to 61% on average) as well as total phenolic compounds measured by Folin–Ciocalteu (P < 0.05). The influence of the debittering on the perceived colour, smell and taste was evaluated by paired comparison tests. The naïve panellists found significant differences not only in taste but also in colour and aroma between FOJ and DOJ; however, preference was not clear.