In this work, oil obtained from seeds of different red grape varieties, grown in the Autonomous Regions of Castilla-La Mancha and Murcia (Spain), was characterized by determining physicochemical and sensory quality parameters, stability, and the composition in fatty acids and sterols. The physicochemical quality parameters (free acidity, peroxide index, K 270 and wax) scored high (meaning low quality) compared with virgin olive oils, while the negative sensory attributes stood out over the positive ones. Therefore, the oil was not considered suitable for table use without undergoing a refining process. The samples showed high linoleic and low linolenic acid contents, while b-sitosterol was the main sterol found. Drying grape seeds with hot air before extraction gave higher physicochemical quality, total phenolic content and stability, and lower wax content in comparison to air-drying of seeds. The drying process affected the sterol composition but not the fatty acid composition.

A dehydration postharvesting treatment is necessary to convert Crocus sativus L. stigmas into saffron spice. Three different dehydration treatments were evaluated: dehydration at room temperature; dehydration with hot air at different temperatures (70, 90, and 110 degrees C); and dehydration following traditional processing in Castille-La Mancha (Spain) with three different heating sources (vineshoot charcoal, gas cooker, and electric coil). The time (between 28 and 55 min) and mean temperature (between 54 and 83 degrees C) conditions for traditional dehydration were established for the first time. The highest coloring strength was obtained when saffron was submitted to higher temperatures and lower times. These findings may be supported by the fact that samples dehydrated at high temperature were more porous than those dehydrated at room temperature, as was observed by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The higher the temperature during the process, the higher the proportion of trans-crocetin di-(beta-D-gentibiosyl) ester, although trans-crocetin (beta-D-glucosyl)-(beta-D-gentibiosyl) and trans-crocetin di-(beta-D-glucosyl) ester decrease while cis-crocins did not change significantly. A thermal aging process reveals that the trans-crocetin di-(beta-D-gentibiosyl) ester increases when saffron is resubmitted to a heating treatment before it is decomposed by the extreme conditions. The picrocrocin extinction during the aging process does not imply a consistent generation of safranal.

No abstract

The surpluses of the wine industry that originate from wine production in the European countries must be reduced. Green harvesting, consisting in collecting the grapes when they are still green, could contribute to the reduction of the yield of vineyards. The green grapes are not suitable for wine production, but they can be used for seed oil extraction. Grape seed oil is a linoleic acid rich oil that has been suggested as an alternative to traditional vegetable edible oils. In this work, grape samples were collected at different stages during berry development for seed oil extraction. The grapes collected at a very early stage showed a very low oil extraction yield compared with that of the samples collected at later stages. The oil from the grapes collected at an early stage had considerably higher sterols content and had a significantly different fatty acid composition compared with those of the oil extracted from grapes collected at later stages. However, the oil samples from grapes collected before veraison did not show significant differences with samples collected after veraison as regards oil extraction yield, fatty acids composition, and total sterol content and composition. Our data suggest that grapes collected from green harvesting near veraison could be suitable for seed oil extraction, with characteristics similar to those of the oil extracted from the seeds of mature grapes.

Mushroom supplementation is an agronomic process which consists of the application of nutritional amendments to the substrates employed for mushroom cultivation. Different nitrogen and carbohydrate rich supplements have been evaluated in crops with a substantial impact on mushroom yield and quality; however, there is still controversy regarding the nutritional requirements of mushrooms and the necessity for the development of new commercial additives. The addition of external nutrients increases the productivity of some low-yielding mushroom varieties, and therefore is a useful tool for the industry to introduce new commercially viable varieties. Spent mushroom compost is a waste material that could feasibly be recycled as a substrate to support a new commercially viable crop cycle when amended with supplements. On the other hand, a new line of research based on the use of mushroom growth promoting microorganisms is rising above the horizon to supplement the native microbiota, which appears to cover nutritional deficiencies. Several supplements employed for the cultivated mushrooms and their agronomic potential in terms of yield and quality are reviewed in this paper as a useful guide to evaluate the nutritional requirements of the crop and to design new formulas for commercial supplementation.