Changes in the phenolic content and free radical-scavenging activity of vacuum packed walnut kernels during storage

In this study, the effects of storage temperature, O2 permeability of packaging materials and variety on phenolic content and free radical-scavenging activity of vacuum-packaged walnut kernels were studied over a 12 months storage period. Methyl gallate (23.70 . 93.75 mg/kg), ellagic acid (137.95 . 569.22 mg/kg), and an ellagic acid pentoside (270.59 . 637.17 mg ellagic acid equivalent/kg) were identified in walnut varieties. While a slight decrease in the amount of ellagic acid was observed during 12 months storage, decreases in the amount of ellagic acid pentoside, total phenolic content and free radical-scavenging activity were severe. The present study concluded that it is possible to protect the phenolic content and antiradical activity of walnut kernels by packaging in Polyamide/Polyethylene laminate pouches having an oxygen permeability lower than 63.40±0.40 (mL/m2/24h at 23°C) under vacuum at 20°C up to twelve months

Effects of Clarification and Storage on Anthocyanins and Color of Pomegranate Juice Concentrates

Whole pomegranates with rinds were processed into juice and then concentrate. Effects of cold clarification and storage temperatures (-23C, 5C, 12C and 20C) on anthocyanins (ACNs), ACN composition and color were determined. Major ACNs in pomegranate juice concentrate (PJC) were identified as cyanidin-3,5-diglucoside (47.9%), delphinidin-3,5-diglucoside (23.2%) and cyanidin-3-glucoside (18.5%). Diglucosides were more stable than monoglucosides during storage. ACN degradation and polymeric color formation were fitted to first-order reaction models. Higher storage temperatures increased the rate of ACN degradation and polymeric color formation in PJCs. Good correlation (r=-0.988) was found between ACN degradation and polymeric color formation during storage. Rate of ACN degradation and polymeric color formation were slower in the PJC obtained from unclarified juice than PJC obtained from clarified juice during storage. © 2012 Wiley Periodicals, Inc

Ultrasound-assisted extraction and (U)HPLC-DAD-ESI-MSn analysis of phenolic compounds from black chokeberries cultivated in Turkey

Phenolic compounds from two black chokeberry cultivars 'Viking' and 'Nero' grown in Turkey were analyzed by high performance liquid chromatography-diode array detection-electrospray ionization-multistage mass spectrometry (HPLC-DAD-ESI-MSn). In the first step, five different solvents were compared to efficiently isolate phenolic compounds by ultrasound-assisted extraction. Three sequential extraction cycles using methanol/formic acid (95:5, v/v) sufficed for exhaustive extraction of anthocyanins, hydroxycinnamic acid derivatives, and flavonol glycosides from black chokeberry within merely 60 sec. A total of four cyanidin glycosides, two hydroxycinnamic acids, and five quercetin mono- and diglycosides were detected in both cultivars. Total anthocyanins (425-438 mg/100 g of fresh weight, FW), hydroxycinnamic acids (173-179 mg/100 g of FW), and flavonols (37 mg/100 g of FW) were determined in a similar range for both cultivars. Complementary, a rapid ultra-high performance liquid chromatography (UHPLC)-DAD method was developed, permitting a high throughput screening of chokeberry phenolics. The established methods were validated considering extraction recoveries, intra- and inter-day repeatability, calibration linearity, limit of detection (LOD), and limit of quantitation (LOQ). UHPLC provided a 2.3 times faster compound separation (30 min) and less solvent consumption than HPLC (68 min)

Catalytic Performances of Various Solid Catalysts and Metal Halides for Microwave-Assisted Hydrothermal Conversion of Xylose, Xylan, and Straw to Furfural

Conclusions Microwave-assisted hydrothermal treatment in the presence of FeCl3 can be applied for both the saccharification of straw biomass and production of furfural from straw biomass

Improving the Functional Performance of Date Seed Protein Concentrate by High-Intensity Ultrasonic Treatment

Date kernel is a plant-derived byproduct that has the potential to be converted into a high-value-added food ingredient, such as protein concentrate, in the food industry. Ultrasound, which is an alternative method for improving the functional properties of food proteins, is an effective physical treatment for modifying protein functionality. Solubility is the main criterion that primarily affects other functional properties of protein concentrates, such as emulsification, foaming, and water and oil binding. The aim of this study is to enhance the techno-functional performance of date seed protein concentrate (DSPC) by maximizing the solubility via a high-intensity ultrasound (HIUS) treatment at a fixed frequency of 20 kHz. The effect of ultrasonic homogenization under varying amplitudes and times (amplitude of 40, 60, and 80% for 5, 10, and 15 min, respectively) on the functional properties of the DSPC was investigated by using the response surface methodology (RSM). A face-centered central composite design (FC-CCD) revealed that the optimal process conditions of HIUS were at an amplitude of 80% for 15 min. The physicochemical and functional properties of the ultrasound-applied concentrate (DSPC-US) were determined under the optimum HIUS conditions, and then these properties of DSPC-US were compared to the native DSPC. The results showed that the solubility of all DSPC samples treated by HIUS was significantly (p < 0.05) higher than that of the native DSPC. In addition, emulsion activity/stability, foaming activity/stability, and oil-binding capacity increased after HIUS homogenization treatments, whereas the water-binding capacity decreased. These changes in the techno-functional properties of the DSPC-US were explained by the modification to the physicochemical structure of the DSPC (particle size, zeta potential, SDS-PAGE, SEM, FTIR, DSC, free SH content, surface hydrophobicity, and intrinsic emission). This work revealed that HIUS could be an effective treatment for enhancing the functional properties of date seed protein concentrate

Acid-catalyzed conversion of xylose, xylan and straw into furfural by microwave-assisted reaction

Furfural is a biomass derived-chemical that can be used to replace petrochemicals. In this study, the acid-catalyzed conversion of xylose and xylan to furfural by microwave-assisted reaction was investigated at selected ranges of temperature (140-190°C), time (1-30. min), substrate concentration (1:5-1:200 solid:liquid ratio), and pH (2-0.13). We found that a temperature of 180°C, a solid:liquid ratio of 1:200, a residence time of 20. min, and a pH of 1.12 gave the best furfural yields. The effect of different Brønsted acids on the conversion efficiency of xylose and xylan was also evaluated, with hydrochloric acid being found to be the most effective catalyst. The microwave-assisted process provides highly efficient conversion: furfural yields obtained from wheat straw, triticale straw, and flax shives were 48.4%, 45.7%, and 72.1%, respectively. © 2011

PUNGENT AND COLOUR COMPOUNDS OF RED PEPPERS

The capcaicinoid amount of red peppers from Solanacea family is used for the evaluation of quality and classification in many countries. Capsaicin is the major pungent principle (69 %) of capsaicinoids. The others are dihidrocapsaicin (22 %), nordihidrocapsaicin (7 %), homocapsaicin (1 %) and homodihidrocapsaicin (1 %). As in most foods, the carotenoids of red peppers are also important compounds. Carotenoids are typical colour pigments and some of them have vitamin A activity. Major carotenoids of ripe fruit of red peppers are capsanthin, capsorubin, ß-carotene and zeaxanthin. Capcaicinoid and carotenoid contents of red peppers grown in many different regions of the world, their properties and roles on the human health were given in this review

Anthocyanin and colour changes during processing of pomegranate (Punica granatum L.; Cv. Hicaznar) juice from sacs and whole fruit

The effects of clarification and pasteurisation on anthocyanins (ACNs) and the colour of pomegranate juice (PJ) produced from sacs and whole fruits were investigated. Clarification caused a loss of 4% of ACNs in juice from sacs (JFS) and a loss of 19% in juice from whole fruit (JFWF). After pasteurisation, there was an 8-14% and 13-9% loss of ACNs from unclarified and clarified JFS and JFWF samples, respectively. Polymeric colour was very high even in unclarified samples (25-29%). Compared to JFS, higher polymeric colour was formed in JFWF. HPLC analyses of PJ revealed that cyanidin-3,5-diglucoside was the major ACN, followed by cyanidin-3-glucoside and delphinidin-3-glucoside. Cyanidin-3,5-diglucoside showed higher stability to clarification and pasteurisation than cyanidin-3-glucoside in both PJ samples. Cold clarification with only gelatin is recommended for PJ. To prevent excessive ACN loss and the formation of brown colouring, PJ should be subjected to minimal heating. © 2011 Elsevier Ltd. All rights reserved