Effect of mechanical leaf removal and its timing on flavan‐3‐ol composition and concentrations in Vitis vinifera L. cv. Pinot Noir wine

Background and Aims: Mechanical leaf removal of Pinot Noir vines was carried out in a commercial vineyard in Waipara, New Zealand in the 2007–2008 and 2008–2009 growing seasons. The aim was to investigate the effects of different timings on flavan‐3‐ol composition and concentrations in Pinot Noir wine produced from the treatments. Methods and Results: Treatments were leaf removal from the fruiting zone 7 days after flowering, 30 days after flowering and at veraison (by visual assessment), and no leaf removal (control). Proanthocyanidin concentrations in berries by the methylcellulose precipitation assay at harvest showed no difference between treatments, although the LR7 wine had the highest methylcellulose precipitable tannin concentration in 2007–2008, the LR30 wine had the highest concentration in 2008–2009 and the NLR wine had the lowest in both years; the 2009 wines had increased concentrations compared to 2008. Greatest concentrations of flavan‐3‐ol monomers by reverse phase high performance liquid chromatography were found in LR7 wines. An increase in the ratio of 2,3‐trans to 2,3‐cis flavan‐3‐ols was observed with earlier leaf removal. The mean degree of polymerisation (mDP) by acid catalysis in the presence of phloroglucinol showed no statistical difference between wines. Conclusions: Early timing of mechanical leaf removal increases proanthocyanidin concentration, but has no influence on the mDP. Increased severity of defoliation and/or higher alcohol levels in the 2008–2009 growing season were responsible for the differences in total tannin concentration compared to the previous year. Significance of the Study: The timing of mechanical leaf removal can influence wine flavan‐3‐ol concentrations.     

Effects of β‐cyclodextrin addition and farming type on vitamin C,antioxidant activity,carotenoids profile,and sensory analysis in pasteurised orange juices

The effects of organic farming, pasteurisation and addition of β‐cyclodextrin on the content of vitamin C, colour, carotenoids and antioxidant capacity of orange juices were studied. After pasteurisation at 98 °C (20 s) and subsequently storage along 145 days at room temperature (20–25 °C), the loss of vitamin C content was around 30%. The effects of the thermal process on carotenoid were clearly observed in lutein (loss of 16% for organic and traditional 8%) and especially β‐cryptoxanthin (loss of 30%). The colour changes were noticeable after the pasteurisation of orange juice and subsequent storage, with significant decreases being observed in lightness and the coordinate a*, while increases were found for coordinates b*, Hue* and chroma. The antioxidant capacity was 0.075 ± 0.01 and 0.053 ± 0.01 mMT mL^?1 for organic and conventional, respectively, with losses around 40% being found at the end of the storage period. The addition of β‐cyclodextrin caused no significant effects on the parameters under analysis. These data showed that strong thermal treatments, such as pasteurisation, adversely affect the nutritional and sensory quality of orange juices.     

High‐molecular‐weight glutenin subunit composition of Pakistani hard white spring wheats grown at three locations for 2 years and its relationship with end‐use quality characteristics

Eleven Pakistani hard white spring wheat cultivars, along with one durum wheat and two hard white American‐grown wheat cultivars, were evaluated for their high‐molecular‐weight (HMW) glutenin subunit composition via sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE). The relationships among different quality characteristics and between these characteristics and HMW glutenin subunits were computed. Three to six HMW glutenin subunits were observed in Pakistani bread wheat cultivars. The presence of HMW glutenin subunits was not affected by growth locations or crop years. However, variations in intensities were observed. Correlations were noticed between certain HMW glutenin subunits and some quality attributes, such as protein, farinograph dough development time, farinograph water absorption, loaf volume and mixograph peak height. The presence of HMW glutenin subunit 20 in the older wheat cultivars C591 and C273, known for excellent chapati quality, indicated a possible relationship between this band and chapati quality. This observation will need to be confirmed by testing a larger number of wheat samples known to have characteristics for both good and poor chapati quality. © 2000 Society of Chemical Industry     

Optimisation of red pepper seed oil extraction using supercritical CO2 and analysis of the composition by reversed‐phase HPLC‐FLD‐MS/MS

Oil extractions from red pepper seed were performed by supercritical CO₂. Three‐level Box–Behnken factorial design (BBD) from response surface methodology (RSM) was applied to optimise the main extraction conditions including pressure, temperature and concentration of modifier (ethanol). The optimum conditions were as follows: extraction pressure, 27.17 MPa; extraction temperature, 47.67 °C; and the added concentration of modifier, 8.11 vol.%. Under the optimum conditions, the oil yield of 18.4% was obtained, which was well matched with the predicted yield. A simple, stable and sensitive method for the simultaneous determination of saturated and unsaturated free fatty acids in extracted oils using 2‐(11H‐benzo[a]carbazol‐11‐yl)‐ethyl‐4‐methylbenzenesulfonate (BCETS) as labelling reagent with fluorescence detection has been developed. All of free fatty acids (FFA) were found to give a linear response with correlation coefficients of >0.9991. The detection limits at a signal‐to‐noise ratio (S/N) of three are in the range of 19.06–41.19 fmol. This method should have powerful potential for the trace analysis of short‐ and long‐chain FFA from edible oils, foodstuff and other complex samples.