Predicting calcium in grape must and base wine by FT-NIR spectroscopy

Calcium content in sparkling wines may not exceed 80 mg/L due to the risk of aggregation with alginate capsules. The high calcium content usually found in wine and must emphasizes the need to develop alternative and appropriate techniques faster and cleaner than atomic absorption spectrometry (AAS). To obtain a robust model to predict calcium content, FT-NIR spectroscopy was used in 98 base white wine samples and 60 must samples from an Alentejo winery. The reference method for calcium determination was AAS technique, with a dry ashing sample procedure, as a prior treatment. Results confirmed the ability of FT-NIR as an alternative technique to AAS, to predict calcium content in grape must and base wine. Advance knowledge of the calcium content in the grape must will help avoid obtaining a mixture of musts with a high calcium content in the same container

THE FATE OF CALCIUM APPLIED THROUGH FOLIAR FERTILIZATION ON OLEA EUROPEAE L.

Olive trees fertilization through foliar pulverization is a more targeted oriented method than the application of chemical fertilizers to the soil. Many factors influence the performance of foliar nutrients sprays such as the presence of leaf cuticle, leaf hairs and leaf surface wax. Calcium is one of the most common macronutrients applied as foliar fertilizer due to its low mobility inside the plants. The presence of calcium in olive fruits, mainly in cell walls, will improve resistance to important pest problems as well as improve fruit quality. The aim of this study was the evaluation in ‘Galega vulgar’ olive trees the efficacy of calcium foliar applications and the subsequent redistribution of this nutrient through the different cell components. Olive trees were sprayed four times from August until veraison with a commercial product containing 34% of calcium, in three different doses. Our results confirmed that calcium applied through foliar pulverization increased calcium deposition in fruit cell wall as well as the total calcium in the fruits. It is also discussed the role of epidermal structures, the hydrophobicity of leaves surface and the presence of cuticle waxes, in the absorption of foliar-applied calcium

Suplementação em cálcio: uma ajuda promissora na prevenção da gafa da azeitona

A antracnose ou gafa da azeitona, é uma das doenças mais importantes que afeta o olival. Esta doença surge pela ação de fungos do género Colletotrichum, que podem levar à completa degradação do fruto tornando-o impróprio para a produção de azeite. Esta doença é mais grave em cultivares suscetíveis como é o caso da Galega vulgar. Sabe-se que os frutos de Galega vulgar têm na sua constituição um tecido epidérmico mais fino do que o de outras cultivares menos suscetíveis à antracnose. O objetivo deste trabalho foi testar o possível efeito protetor da suplementação em cálcio foliar contra a antracnose da azeitona, na cultivar Galega. Para esse efeito procedeu-se à aplicação de um produto comercial que doseia 34% de cálcio, que foi aplicado num olival tradicional, num ensaio com 3 modalidades (D0, D1 e D2): D0 em que não houve aplicação do produto; D1 em que se aplicou a dose de 2kg/ha; e D2 em que se aplicou 4kg/ha. Estas aplicações foram realizadas 4 vezes, de agosto a outubro. A amostragem de frutosfoi repetida várias vezes, durante toda a época de colheita. Os frutos amostrados foram desinfetados superficialmente, inoculados em câmara húmida com uma suspensão de Colletotrichum nymphaea e posteriormente foram avaliados os níveis de infeção. Nas diferentes amostras foi ainda quantificado o teor de cálcio nas paredes celulares por espectrofotometria de absorção atómica, após digestão ácida das amostras. Verificou-se que, 15 dias após a inoculação a percentagem de frutos infetados na modalidade D0 foi de 90%, na D1 foi de 75% e na D2 foi de 20%. Observou-se ainda que a aplicação de cálcio foliar levou a um aumento deste catião na fração das paredes celulares dos frutos, o que poderá ter contribuído para os menores níveis de infeção por Colletotrichum nymphaea observados

Terroir influence on quality of ‘Crimson’ table grapes

The terroir concept can be defined as the effect on food sensory features of the uniqueness of the place, which gives food products a particular taste, mainly due to soil and climate characteristics. The aim of the present study was to understand the relationship between the physiological behaviour of vineyards, soil characteristics and final quality of ‘Crimson’ table grapes. Soluble Solids Content (SSC) and texture properties of berries varied significantly between the two vineyards. Unexpectedly, the vineyard which had the lower leaf chlorophyll content (9.99 mg m−2 ± 2.73), produced the heavier berries (5.82 g ± 0.21) with higher SSC values (22.03°Brix ± 0.23). Only slight differences for phenolic compounds and antioxidant capacity were observed between grapes from the two vineyards (p > 0.05). As previously reported by other authors, the balance between soil and berry mineral content seems to indicate that mineral nutrient uptake by the vine or soil ability to provide nutrients, did not step in significantly on grape quality. Regarding sensory evaluation, consumers found differences between grapes from the same cultivar growing in the same region but from two distinct vineyards (p < 0.05), which was corroborated by the differences found in some instrumental measurements