Nerea Jiménez-Moreno

Current Knowledge about the Presence of Amines in Wine

This review discusses those factors that have an influence on amine concentration in wine, as well as the vinification stages when these amines are formed and their evolution during the storage of the product. It also outlines the importance of these biogenic and volatile amines both in the sensorial aspect as well as the toxic action. Amines are nitrogenous bases of low molecular weight, which are especially found in food and beverages from the fermentation process, as is the case of wine. Amine concentration in wine can be very variable, ranging from trace levels up to 130 mg/L, so it is difficult to predict the content of these compounds in the product. At present this variability is of some concern in many countries, especially for the toxic effect that some amines can have on people who are susceptible to these substances. Consequently, it is necessary to develop new studies to learn more about the factors, which have an influence on their concentration in wine, and to establish limits for these substances in the product so as to prevent any toxic effects on the consumer.

Influence of Nutrients Addition to Nonlimited-in-Nitrogen Must on Wine Volatile Composition

Several factors can affect production of volatile compounds in wines, including nutritional differences in the must. Among the nutritive compounds of must, the amino acids are of great importance due to the fact that they can serve as precursors of esters or may play an indirect role in supporting cellular metabolic activities. The aim of this study was to examine the influence of the addition of a complex nutrient such as the yeast autolysate to a nitrogen nonlimited must of Chardonnay variety on the formation of esters, alcohols, and acids. Yeast autolysate supplied fatty acids, amino acids (above all, tyrosine, threonine, and glutamic acid), and an insoluble fraction formed by yeast cell walls. It was observed that the nutrient enrichment of the Chardonnay must did not favor the formation of either esters or alcohols. These results demonstrate that when juice is sufficient in nitrogen, the addition of amino acids does not improve the volatile composition of wine. Under these conditions, the amino acids would have probably been used for other cellular processes that do not produce volatile compounds.

Sorption of volatile phenols by yeast cell walls

Yeast walls can retain different wine compounds and so its use is interesting in order to eliminate harmful substances from the must which affect alcoholic fermentation (medium chain fatty acids) or which affect wine quality in a negative way (ethyl phenols, ochratoxin A). The aim of this study was to examine the capacity of commercial yeast cell walls in eliminating volatile phenols (4-ethylphenol and 4-ethylguaiacol) from a synthetic wine that contained 1 mg/L of each one of these compounds. The binding of these compounds to the wall was quite fast which would seem to indicate that the yeast wall-volatile compound union is produced in the outer surface layers of this enological additive. The cell walls used reduced the concentration of 4-ethylphenol and 4-ethylguaiacol, although it would seem that on modifying the matrix of the wine the number of free binding sites on the walls is also modifi ed.

Therapeutic applications of rose hips from different rosa species

Rosa species, rose hips, are widespread wild plants that have been traditionally used as medicinal compounds for the treatment of a wide variety of diseases. The therapeutic potential of these plants is based on its antioxidant effects caused by or associated with its phytochemical composition, which includes ascorbic acid, phenolic compounds and healthy fatty acids among others. Over the last few years, medicinal interest in rose hips has increased as a consequence of recent research that has studied its potential application as a treatment for several diseases including skin disorders, hepatotoxicity, renal disturbances, diarrhoea, inflammatory disorders, arthritis, diabetes, hyperlipidaemia, obesity and cancer. In this review, the role of different species of Rosa in the prevention of treatment of various disorders related to oxidative stress, is examined, focusing on new therapeutic approaches from a molecular point of view.

Chemical composition of rosehips from different Rosa species: an alternative source of antioxidants for the food industry

ABSTRACT It is important to explore new sources of natural additives because the demand for these compounds by consumers is increasing. These products also provide health benefits and help in food preservation. An unexplored source of nutrients and antioxidant compounds is rosehip, the fleshy fruit of roses. This work compares the antioxidant compound (vitamin C, neutral phenols and acidic phenols) content of four Rosa species rosehips: R. pouzinii, R. corymbifera, R. glauca and R. canina from different geographical zones. Results show quantitative variability in ascorbic acids and neutral phenols content, and quantitative and qualitative differences in acidic phenol content, depending on species. Vitamin C concentration was highly variable depending on species, R. canina being the one with the highest concentration and R. pouzinii the one with the lowest content. Variability was found in total neutral polyphenols concentration and a correlation between freshness of the rosehips and concentration of neutral polyphenols was also found. Significant differences were found in the acidic phenols content among the studied species. Generally antioxidant activity was higher in the vitamin C fraction.

Effects of reduced levels of sulfite in wine production using mixtures with lysozyme and dimethyl dicarbonate on levels of volatile and biogenic amines

ABSTRACT Sulphur dioxide (SO2) is an important preservative for wine, but its presence in foods can cause allergies and this has given impetus to the research for alternatives. The aim of this study was to reduce levels of sulfite in wine production using mixtures with lysozyme and dimethyl dicarbonate and examine the influence on levels of volatile and biogenic amines. To do so, vinifications were carried out using lysozyme, dimethyl dicarbonate (DMDC) and mixtures of these with SO2 in different concentrations (25 and 50 mg l−1). Results were compared with a control vinification with only SO2 (50 mg l−1). Mixing low concentrations of SO2 with lysozyme and DMDC reduced the concentration of biogenic amines (histamine, tyramine, putrescine, cadaverine, phenylethylamine + spermidine and spermine). In general, the total concentration of volatile amines (dimethylamine, isopropylamine, isobutylamine, pyrrolidine, ethylamine, diethylamine, amylamine and hexylamine) was higher in the sample fermented only with SO2. The concentrations of amines with secondary amino groups (dimethylamine, diethylamine, pyrrolidine) were higher in the sample only fermented with SO2 than those fermented with DMDC and lysozyme or with a mixture of preservatives. When SO2 was the only preservative in wine, total amine concentration (biogenic and volatile amines) was higher than for the rest of the treatments. Lysozyme by itself, and lysozyme mixed with SO2, both reduced the formation of biogenic amines but given the antioxidant activity of SO2 the use of the preservative mixture seems more advisable.

Oak wood extracts applied to the grapevine. An alternative to obtain quality Garnacha wines

Stomata in leaves regulate gas interchange and transpiration in the grapevine and through these pores both the penetration of aqueous solutions with nutrients as well as the excretion of products take place. The aim of this work was to study the influence of spraying the vineyard with toasted and untoasted oak extracts on the volatile composition and on the organoleptic quality of wine made from Garnacha grapes. The results were compared with a Garnacha control wine obtained with grapes sprayed with distilled water. The absorption of the compounds from the oak wood extracts was irregular and some of these compounds were modified by the yeast during fermentation so as to prevent fermentation problems. This was observed particularly in the case of furfural which were transformed into furfuryl alcohol by yeast in order to avoid irreversible cellular damage. On applying a discriminant analysis to the concentration of volatile compounds in the wines, the three treatments (control, toasted and untoasted oak extracts) were differentiate. The wine obtained from grapes treated with toasted oak extract showed a more intense wood aroma after 18months of bottle aging than the other wines. Likewise, spicy aromas were found to be more intense in the samples treated with some type of oak wood extracts.