Hard-to-cook phenomenon in beans: Changes in antinutrient factors and nitrogenous compounds during storage

Five different bean varieties (Phaseolus vulgaris) from Kenya, which were either freshly collected or stored for 5 years in tropical conditions (30–40°C; >75% humidity), were compared for their cooking characteristics. The beans under storage develop an irreversible phenomenon classified as ‘hard-to-cook’ (HTC) which results in undesirable characteristics limiting their acceptability. Our aims were to determine the effects of the HTC phenomenon on the proteins and antinutrient factors in these beans. Both fresh and HTC beans contained nutritionally significant amounts of lectins, trypsin and α-amylase inhibitors. HTC samples had higher lectin and lower α-amylase inhibitor contents, while the amounts of trypsin and chymotrypsin inhibitors were the same. Storage appeared to reduce water-extractable nitrogen. Fractionation with sodium dodecyl sulphate also showed that less protein may be available in HTC than fresh beans. We established that the undesirable changes in beans, such as increased cooking time, which often accompany the storage of harvested seeds under tropical conditions produce an overall decrease in soluble-N fractions, particularly proteins. The results can provide guidelines on how to utilise these seed(s) and their products. Furthermore, appropriate processing is needed to reduce their antinutrients for human nutrition.     

Wasted bread flour as a novel ingredient in cake making

Bread is one of the most wasted products in both industry and retail. This study analysed the use of bread flour of various particle sizes (1000 μm, 500 μm and 200 μm) in different percentages for sponge formulations (10% and 20%) and layer cakes (10%, 20% and 30%). Viscosity, microstructure and density of batters, as well as specific volume, texture and colour of cakes were evaluated. The inclusion of bread flour change batter microstructure. Viscosity does not affect the sponge batters but it tends to increase in the layers, mostly in the case of finer flours. The specific volume is reduced in sponge cakes while hardness is generally increased, even with the lowest percentages of bread flour. In layers, this reduction in volume is only visible at the highest doses of flours below 500 microns with no changes in hardness.     

Analysis of non-coloured phenolics in port wines by capillary zone electrophoresis Influence of grape variety and ageing

 Different experimental varietal port wines were analysed in order to determine differences in the concentrations of phenolic compounds between some commonly used grapes varieties (Touriga Francesa, Touriga Nacional, Tinta Roriz and Tinta Barroca). Although all samples had the same qualitative pattern of non-coloured phenolic compounds, Touriga varieties contained more than twice the concentration of these compounds compared to the Tinta varieties. A preliminary study of the effect of ageing on these compounds revealed an overall increase in those components associated with the bitter or astringent characteristics of food and beverages (tyrosol, gallic acid and catechin). Received: 1 August 1997     

Atmospheric gas-particle partitioning of polycyclic aromatic hydrocarbons in high mountain regions of Europe

Atmospheric concentrations and gas-particle partitioning of polycyclic aromatic hydrocarbons (PAH) have been determined at three remote mountain areas in Europe. Gas-phase mean concentrations of total PAH (20 individual compounds) were very similar at all sites, ranging from 1.3-2.6 ng m(-3) in the Pyrenees (Spain) to 2.7-3.7 ng m(-3) in the Alps (Austria) and Caledonian mountains (Norway). A seasonal variability was observed, with the highest levels found in winter. The seasonal differences were reflected better in the particle-associated PAH, showing the increase of PAH emissions in the colder months and a temperature dependence of the gas-particle partitioning. Significant geographical differences were also observed for particulate PAH, indicating a greater influence of regional sources than in the gas phase. Partitioning of PAH between gas and particulate phases was well-correlated with the subcooled liquid vapor pressure in all samples, but with slopes significantly steeper than the expected value of -1. These steeper slopes may reflect the occurrence of a nonexchangeable PAH fraction in the aerosols, likely associated to the soot carbon phase. Comparison of absorption to organic matter and soot carbon using the octanol-air (Koa) and soot-air (Ksa) partitioning coefficients shows that, despite uncertainties on estimated organic matter and soot carbon contents in the sampled aerosols, Koa underpredicts aerosol PAH concentrations by a factor of 0.6-2 log units. In contrast, predicted and measured high mountain aerosol PAH differ by 0.2-0.6 log units when Ksa is considered. The results point to soot carbon as the main transport medium for the long-range distribution of aerosol-associated PAH.     

Storage affects the phenolic profiles and antioxidant activities of cherries (Prunus avium L) on human low‐density lipoproteins

Four sweet cherry cultivars (cvs), Burlat, Saco, Summit and Van, were analysed at harvest and after storage at 2 and 15 °C for 30 and 6 days respectively. Phenolic profiles in methanolic extracts of freeze‐dried samples of the fresh and differently stored cherries were quantified by high‐performance liquid chromatography. Hydroxycinnamates dominated in all samples and represented 60–74% by weight of the phenols in the fresh and stored samples of the cvs Saco, Summit and Van, and 45% by weight of the phenols in the cv Burlat samples, which were richer in anthocyanins. The relative and total levels of hydroxycinnamates, anthocyanins, flavonols and flavan‐3‐ols varied among cultivars and during storage. Storage at 15 °C increased the phenol levels, particularly the cyanidin‐3‐rutinoside concentration. Cold storage induced decreased total phenol levels in the cvs Summit and Van but increased total phenol levels in the cvs Burlat and Saco. Phenolic cherry extracts inhibited low‐density lipoprotein oxidation in vitro in a dose‐dependent manner. Extracts of freshly harvested cherries exhibited significantly higher antioxidant activities than extracts of stored samples. The cv Summit samples had the highest antioxidant activity. Differences in the antioxidant effects of the cherry samples were positively correlated with their levels of p‐coumaroylquinic acid (p < 0.1) but negatively correlated with their cyanidin‐3‐rutinoside levels (p < 0.05). Copyright © 2004 Society of Chemical Industry     

Determination of phenolic compounds of ‘Sikitita’ olive leaves by HPLC-DAD-TOF-MS. Comparison with its parents ‘Arbequina’ and ‘Picual’ olive leaves

‘Sikitita’ is a new olive cultivar developed in Spain by crossing the cultivars ‘Picual’ and ‘Arbequina’. The phenolic fraction of olive leaves (Olea europaea L.), is purported to have good anti-oxidative properties which help to prevent several health problems. To our knowledge, no studies are available on the phenolic fraction of ‘Sikitita’ olive leaves or any other new cultivar developed from breeding. Thus, the identification and quantification of the phenolic fraction of ‘Sikitita’ olive leaves by HPLC-DAD-MS were studied and compared with those of its parent cultivars. The three cultivars were grown under the same agronomic and environmental conditions in the same orchard. The quantification was performed using HPLC-DAD, whereas qualitative data were acquired using HPLC-MS. It was thus possible to identify 30 different compounds, two of which have been tentatively characterized for the first time in olive leaves of Spanish cultivars. Significant differences between cultivars were observed for almost all the compounds. Results for ‘Sikitita’ olive leaves presented a higher degree of similarity with respect to ‘Picual’ than to ‘Arbequina’. Further work will monitor the time course of phenolic compounds over the growth period.     

Comparative study of improved vs. traditional apple cultivars and their aptitude to be minimally processed as ‘ready to eat’ apple wedges

The development of fresh-cut apple products requires the reconsideration of cultivar selection because different characteristics are required compared with those characteristics for the fresh market. The aim of this work was to evaluate four improved cultivars (‘Modì’, ‘Ariane’, ‘Fuji Kiku 8’ and ‘Pink Lady’) and to compare these cultivars with traditional cultivars (‘Golden Smoothee’ and ‘Granny Smith’). Cultivars were evaluated according to physicochemical parameters and nutritional, enzymatic, and sensory aspects. Next, the cultivars were peeled, cut, treated with different antioxidant treatments, packaged in polypropylene trays and stored at 4 °C. After seven days of storage, physicochemical parameters and visual assessment were determined. As whole apples, the improved cultivars were notable for their sensory characteristics. Moreover, two of them (‘Modì’ and ‘Ariane’) presented the highest amount of total phenols and vitamin C, respectively. After processing and storage, certain of the improved cultivars presented better aptitude for minimal processing. For instance, ‘Modì’ showed high suitability, and ‘Fuji Kiku 8’ was notable for its sensory quality after seven days of refrigerated storage. Among antioxidant treatments that were assayed, 40 g/L NatureSeal^® demonstrated the best results in terms of physicochemical parameters, visual assessment and sensory quality.     

Anthratectone and Naphthotectone,Two Quinones from Bioactive Extracts of <Emphasis Type="Italic">Tectona grandis</Emphasis>

Two new quinones, (an isoprenoid quinone, and a dimeric anthraquinone) named naphthotectone and anthratectone, respectively, were isolated from bioactive leaf extracts from Tectona grandis. Their structures were determined by a combination of 1D and 2D NMR techniques. The bioactivity profile of naphthotectone was assessed using the etiolated wheat coleoptiles bioassay in aqueous solutions at concentrations ranging from 10⁻³ to 10⁻⁵M, as well as the standard target species lettuce, cress, tomato, and onion. Naphthotectone showed high level of activities in both bioassays. This fact, along with the presence of this compound as the major component in Tectona grandis, suggests that it may be involved in the allelopathic activity previously described for this species, and probably in other defense mechanisms.