Lipoxygenase and carotenoids: A co-oxidation story

Lipoxygenases (LOXs), widely found in plants, fungi, and animals, are a large family of monomeric proteins with non-heme, non-sulphur, iron cofactor containing dioxygenases that catalyze the oxidation of polyunsaturated fatty acids such as linoleic, linolenic and arachidonic acid to yield hydroperoxides. Some LOX isoenzymes have the capacity to co-oxidise also the carotenoids. Carotenid biosynthesis occurs only in bacteria, fungi and plants where they have established functions that include their role as antenna in the light-harvesting proteins of photosynthesis, their ability to regulate light-energy conversion in photosynthesis, as well as the ability to protect the plant from reactive oxygen species, and coloration. In humans, some carotenoids (the provitamin A carotenoids: α-carotene, β-carotene, γ-carotene and the xanthophyll β-cryptoxanthin) are best known for their conversion into vitamin A. Lipoxygenase has negative food-related implications for color, off-flavour and antioxidant status of plant based foods. Up to now, β-carotene seems to attract more attention in developing strategies for food processing to prevent LOX-mediated deteriorations such as oxidation, rancidity, and off-flavor. More research is necessary for transferring the in vitro mechanistic studies on the LOX inhibition in vivo. Other carotenoids like lutein, zeaxanthin, β-cryptoxanthin in pure form as well as in natural extracts could be good candidates for LOX inhibition through their antioxidant action.Keywords: Lipoxygenase, carotenoids, oxidationAfrican Journal of Biotechnology Vol. 12(20), pp. 2786-279

The Behaviour of some Recommended Grapevine Cultivars in a Sustainable Crop System to the Eriophyid Mites Attack

The behaviour of some vine cultivars when attacked by the eriophyid mites,Colomerus vitis Pagenstecher which causes grapevine erinose and Calepitrimerus vitis Nalepa, the agent that causes acariosis, is extremely divers, and inconsistent. Some cultivars are resistant under certain conditions (locations), while others are more sensitive. The purpose of this study is to establish the resistance/tolerance of some cultivars to the attack of eryophyid mites, the main pests in the vineyards of Transylvania. The experiments were placed in the experimental plantations of SCDVV Blaj located in the Tarnave vineyard plantated with cultivars: Brumăriu, Fetească regală, Pinot gris, Traminer roz, Muscat Ottonel, Sauvignon blanc, Riesling italian, Blasius, Selena. By analysing the symptoms on the before mentioned cultivars, the attack degree (AD%) varied form 1% for Selena to 47% for Blasius. Among the cultivars, in 2020 Brumăriu has the highest AD% caused by Colomerus vitis with 18.82 %, compared with Pinot gris who had the lowest attack rate 0.08%. All the cultivars were midresistant and resistant against the eriophyid mites, with one exception, Brumăriu has an Attack Degree (AD %) of 18.82%, at the attack of Colomerus vitis

Sulfur dioxide dinamic in Sauvignon Blanc and Neuburger dry white wines

The aim of this study is to evaluate the sulfur dioxide dinamic in two dry white wines Sauvignon blanc and Neuburger produced in Tarnave vineyard in order to check if there is any grape cultivar influence on this compound addition. Four wines (Sauvignon blanc 2018 and 2019 and Neuburger 2018 and 2019) were analysed for the free and total SO2 content during the four stages of vinification and storage: harvest, fermentation, maturation and storage for two years. At the maturation stage, for all these samples the following parameters were also measured: alcohol content (%), total acidity (g/L tartaric acid), volatile acidity (g/L acetic acid), dry extract (g/L), non-reducingdry extract (g/L), relative density at 20°C, total sugars (g/L), glucose and fructose (g/L). For the samples studied in this work, it was determined an increasing concentration of free and total SO2 starting with harvest continuing with fermentation, maturation, the firsty ear of storage and finishing with the second year of storage. Only for the free SO2 at the harvest stage, a cultivar influence was observed. In this study, the limits were between 6.25±1.25 mg/L and 32.55±1.25 mg/L for the dosed free SO2 and between 65.25±0.25 mg/L and 190.40±4.60 mg/L for total SO2. The analyzed wines kept their varietal characteristics and organoleptic properties, as Qualified Denomination of Origin (DOC) Târnave wines, with an admitted SO2 content