Thermal Degradation Kinetics of Anthocyanins and Visual Color of Blood Orange Juice

Thermal degradation kinetics of anthocyanins and visual color （Hunter α value） of blood orange juice were studied at selected temperatures （70-90℃）. Results indicated that both the thermal degradation of anthocyanin and visual color all followed first-order reaction kinetics, and they could be expressed by Arrhenius equation. The activation energy values for the anthocyanins degradation and visual color degradation were 55.81 and 47.51 kJ tool-1, respectively. The linear relationship between visual color and anthocyanin content was obtained. Furthermore, during thermal processing of blood orange juice, the formulas about the linear relationships showed no significant difference at selected temperatures. So, the relationships between visual color and anthocyanins content during thermal processing at selected temperatures could be described by the same equation： α＊/αo＇=0.559（C/Co）＋0.43. It might be inferred that visual color measured instantaneously by tristimulus colorimeters for on-line quality control, could be used to predict the anthocyanins degradation during thermal processing of blood orange juice.

Nutritional Composition of Orange Juice: A Comparative Study between French Commercial and Home-Made Juices

The study aimed to compare the nutritional composition of commercial and home-made orange juices with a fruit content of 100%, i.e., without dilution with water and without addition of sugars or any other sweeteners. Orange juice samples (n = 12 for both types of juice) were representative of the French market and of French consumers’ habits as determined by a consumer survey. The results showed that both types of juices contained the same concentrations in total sugars and polyphenols and had low levels of dietary fiber (P > 0.05 for all parameters). Commercial orange juice contained less vitamin C (P = 0.035) and folate (P = 0.002) than home-made juice (15% and 27% less, respectively), probably owing to the vitamin degradation that may occur during industrial production (e.g., during pasteurization) and storage of commercial orange juice. The observed differences were of relatively small magnitude overall, however, and within the expected ranges for vitamin loss due to pasteurization and storage at ambient temperature. Indeed, commercial orange juice contained 85% of the vitamin C concentration measured in home-made juice, showing that vitamin C was well preserved in commercial juice. Another study with a larger number of samples would be needed to confirm these observations.

Quantification of Flavonoids in Brazilian Orange Peels and Industrial Orange Juice Processing Wastes

The flavonoid content in orange peels of different Brazilian citrus varieties such as bahia, lima, lima-of-persian, morcote, pera, ponkan, seleta, cravo, kinkan and pomelo was assessed. Industry processing juice wastes such as bagasse, bagasse residues, animal feeding bagasse, pulp WEUE and CORE-wash were also analyzed. The HPLC analysis indicates that the most abundant flavonoids found in these Brazilian citrus peels are hesperidin and naringin. The solvents used are selective for flavonoid extraction, and depending on their polarity, glycoside or aglycone flavonoids are extracted. The use of multivariate analysis shows that DMSO is the best solvent to extract glycosides flavanones while hexane displays high selectivity in the extraction of polymethoxylated flavones. The flavonoids present in the orange wastes, obtained at different stages of the industrial processing, are qualitative and quantitatively different. The identification and quantification of the flavonoid composition in each Brazilian citrus variety were evaluated and allowed the selection of the best solvent for the extraction of each specific class of flavonoids. These compounds were found to be more abundant in the fruit peels than in their juices, revealing their great industrial potential. The residual portion of the processing juices is also rich in flavonoids, depending on the processing step.

Extended Gate Field Effect Transistor Based Measuring of the Vitamin C content of Orange Juice

An extended-gate field effect transistor (EGFET)of SnO_2/ITO glass was applied to manufacture the vitamin C sensor.Therefore,we immobilized the ascorbate oxidase with 3-glycidoxypropyltrimethoxysilane (GPTS)method to measure the different concentrations of the vitamin C solution in an optimum measurement environment.In order to find the best measurement conditions of the biosensor,we studied the vitamin C sensor in different pH values of the phosphate buffer solution (PBS).Additionally,we used experimental results to discuss the response time and response voltage to compare vitamin C with orange juice for the vitamin C sensor.

Multielement determination in orange juice by ICP-MS associated with data mining for the classification of organic samples

The aim of this study was to discriminate organic from conventional orange juice based on chemical elements and data mining applications.A comprehensive sampling of organic and conventional oranges was carried out in Borborema,state of Sao Paulo,Brazil.The fruits of the variety Valencia(Citrus sinensis(L.)Osbeck)budded on Rangpur lime(Citrus limonia Osbeck)were analyzed.Eleven chemical elements were determined in 57 orange samples grown in organic and conventional systems.In order to classify these samples,data mining techniques(Support Vector Machine(SVM)and Multilayer Perceptron(MLP))were combined with feature selection(F-score and chi-squared).SVM with chi-squared had a better performance compared with the other techniques because it reached 93.00% accuracy using only seven chemical components(Cu,Cs,Zn,Al,Mn,Rb and Sr),and correctly classified 96.73% of the samples grown in an organic system.

Appraisal of Improvement in Physiological and Metabolic Processes by Exogenously Applied Natural and Synthetic Ascorbic Acid in Okra(Abelmoschus esculentus L.)Fruit Subjected to Water Deficit Stress

To counteract the effects of drought stress,scientists have adopted several approaches including the use of different chemicals both inorganic and organic,which is contemplated as a highly efficient and cost-effective shot-gun approach.Ascorbic acid(AsA)is a potential organic substance,which widely occurs in plants,and is considered to be an effective antioxidant to counteract reactive oxygen species(ROS).Thus,a pot experiment was performed to assess the relative mitigating impacts of synthetic AsA and naturally occurring AsA in the form of lemon juice(LJ)and orange juice(OJ)on two cultivars of okra(Abelmoschus esculentus L.)namely Sabz Pari and Bhindi Sanwali under varying water deficit conditions.After 30 days of seed germination,okra seedlings were subjected to different irrigation regimes,i.e.,water deficit stress[(65%and 50%F.C.)and control conditions(100%F.C.)].Different levels of AsA[control(no spray),14 mg L^(−1)LJ,24 mg L^(−1)OJ and 150 mg L^(−1)AsA]obtained from different sources were applied as a foliar spray to control and water-stressed plants.Drought stress prominently reduced plant growth and yield attributes of the okra cultivars.Water-deficit conditions(65%and 50%F.C.)substantially decreased the fruit chlorophyll(a,b)pigments and the activity of superoxide dismutase(SOD)enzyme,while an increase was observed in the contents of fruit’s hydrogen peroxide(H_(2)O_(2)),malondialdehyde(MDA),total phenolics,total soluble sugars,AsA,and total soluble proteins.Drought stress also increased the activities of antioxidant enzymes like peroxidase(POD)and catalase(CAT).However,plant growth and yield attributes,fruit chlorophyll pigments,total phenolics,total soluble sugars,total free amino acids,total soluble proteins,AsA,GB,H_(2)O_(2),and the activities of antioxidant enzymes(POD and CAT)were increased by the AsA exogenous treatment in both okra cultivars under water deficit and control conditions.Overall,LJ and OJ were more effective than the synthetic AsA in upregulating the physiological and metabolic processes of okra plants.So,cost-effective as well as multi-nutrient natural sources of AsA could be suggested for alleviating the harmful effects of water deficit stress on plants.