What are seedless table grapes?

Grapes are one of the most commonly produced fruit crops in the world and an important fruit commodity that allows good profits to producers. According to their characteristics, grapes can be considered for different uses: wine production (varieties with higher acidity and moderate sugar content), table grapes for fresh consumption (varieties with low acidity, low sugar, and specific standards of size, color, and shape), and raisins (varieties with low acidity and high sugar). In the last years cultivation and consumption of table grapes (Vitis vinifera L.) has increased considerably, mainly due to seedless varieties. Consumers appreciate the absence of seeds and are willing to pay more for sweeter and more firm seedless grapes. However, for many people the term “seedless” has a negative connotation, associated with negative health effects or even genetic manipulation. Seedless grapes exist naturally or may be manipulated by plant breeders without using genetic engineering techniques. Is possible to distinguish two mechanisms of seedlessness: parthenocarpy (when the ovary can develop without fertilization of the ovum) and stenospermocarpy (embryo abortion occurs after fertilization, and partially developed seeds or traces of seed are visible). Shelf-life of seedless grapes is expected to be longer than seeded fruits, because seeds produce hormones that activate senescence. The current table grapes breeding programmes are designed to obtain varieties with good characteristics and mandatorily seedless. So, the absence of seeds, shape, colour, skin thickness, resistance against diseases and pests, ability to be transported without damage and shelf-life are the main criteria to select new varieties. However, those who think that these new seedless table grape varieties are a new development, you are mistaken! There are records of this type of grapes since the 19th century. The most widely commercialized seedless table grapes varieties in the world are Thompson seedless (first seedless variety cultivated in the world), Crimson and Autumn Royal. In recent years, the post-harvest research group at the University of Évora has developed several works, in partnership with regional enterprises, in the characterization and quality evaluation of several varieties of seedless table grapes. This work was supported by Portuguese National Funds through FCT – Fundação para a Ciência e a Tecnologia under Project UIDB/05183/2020 (MED). S. Ricardo-Rodrigues acknowledges a PhD grant from FCT (2021.07663.BD)

Effect of clove essential oil coating in pork meat conservation and texture

Essential oils are complex mixtures of secondary plant metabolites from aromatic plants. There are recognized for having countless biological activities (including antibacterial, antiviral and fungicidal) and being suitable to replace chemical additives for food preservation1. Clove essential oil is considered safe for food use and contains a high phenolic content that provides many biological activities. In this work two formulations of clove essential oil coating were studied, 50 ppm and 500ppm. This coating was applied in pork meat in three different modalities: control, 50 ppm of clove oil edible coating and 500 ppm of clove oil essential oil. During one year, the antioxidant activity of this essential oil coating was studied using the DPPH radical method2. Microbiological analysis included the counts of mesophilic and psychotropic microorganisms, mold, yeasts and enterobacteria. Warner-Bratzler (WB) shear force was performed has rheological analysis, and colorimetric measurements were done according to the protocol of Caine et al. (2003)3. Sensory evaluation was performed with a trained sensory panel following international standards. The antioxidant capacity of the edible coatings studied increased during the first 6 months of conservation, although there weren’t found statistical significative differences in the antioxidant capacity of the different clove formulations. When it comes to microbiological analysis, mesophilic aerobic bacteria seem to decrease during conservation, although with no statistical significative differences between different modalities. Enterobacteria, mold and yeast content didn’t seem to be affected by the clove oil coating application, since there weren’t found statistical significative differences between them. The application of the clove essential oil didn’t seem to affect sheer force of color in different modalities. Finally, regarding sensory analysis, the panel couldn’t find differences between the different meat modalities, namely in flavours, which means that the tested clove edible coating concentration doesn’t have a negative impact on this parameter in meat. Considering these results, the clove essential oil edible coating seems to be a good alternative to food other chemical food preservatives to use in pork meat conservation for the period of one year, since it keeps a high antioxidant capacity during this period, doesn’t affect sensory properties and keeps the microbial count low