Optimisation of blueberry (Vaccinium corymbosum L.) press residue extraction using a combination of pectolytic enzyme and ultrasound treatments

Blueberries are one of the most popular and widely consumed berries, they are usually consumed fresh, dried or processed into juice. During the production of juices large quantities of berry press residues are generated, which are an industrial by-product and they accumulate as food waste. Optimal management of this industrial fruit by-product could help in utilising berry press residues with the purpose to valorise and add economic value. Blueberry press residues consist of skins and seeds which hold valuable compounds with antioxidant activity –polyphenolics. To facilitate the objective of bioactive compound release, the cell walls must rupture. Pectolytic enzymes could be used to degrade the structural polysaccharides of the berry skin cell wall, thus releasing the contents of the cells into the extraction medium. The physical characteristics of berry skins allows the use of pectolytic enzymes for the disruption of cells; however, the effects of enzymatic hydrolysis could be further improved using ultrasound. In this study the combined effects of enzyme and ultrasonic treatments were evaluated and optimised using the Response Surface Methodology approach in order to increase the release of polyphenolic compounds (especially anthocyanins). The optimised method was further tested to evaluate the application potential of enzyme and ultrasound treatment to prepare blueberry or lingonberry juice with increased antioxidant activity and more vibrant colour. The obtained results provide an optional method of berry press residue valorisation to produce higher quality juice or extract bioactive compounds from this type of food-waste.

Effects of a Small Increase in Carbon Dioxide Pressure during Fermentation on Wine Aroma

The present study tested the effect of a slight increase in pressure (from 0 to 1 bar) during the fermentation on the wine aroma profile. Fermentations were carried out with a commercial dry yeast on Sangiovese juice in the absence of berry skins. The wine samples fermented under slight overpressure conditions were found to be significantly different from the control samples produced at atmospheric pressure in relation to several chemical compounds. Concentrations of many esters (i.e., isoamyl acetate, ethyl acetate, ethyl hexanoate, hexyl acetate, ethyl dodecanoate, and ethyl tetradecanoate), and acids (i.e., hexanoic acid, octanoic acid, and decanoic acid) increased, while concentrations of two acids (i.e., isobutyric and isovaleric acid) decreased. These differences, notably the higher concentration of esters, are usually associated with a more intense fruity attribute. Triangular sensory tests revealed that the significant chemical differences were also perceivable; hence, introducing a slight pressure increase during the alcoholic fermentation could be a useful tool in managing the aroma profile of wine.

Topical use of resveratrol: technological aspects

Resveratrol is a natural polyphenolic phytoalexin found in grapes, berry skins, roots of Japanese knotweed and is reputed as an excellent antioxidant, anti-inflammatory, neuro- and cardio- protective agent. Resveratrol has also beneficial effects in therapy of different skin conditions such as acne, exfoliative eczema, psoriasis and is known to provide a protection against ultraviolet radiation-mediated oxidative stress. However, its low oral bioavailability and short biological half- life compromise its beneficial therapeutic effects; therefore, its topical application is a practical approach in the treatment of various cutaneous disorders. Challenges associated with the development of topical resveratrol drug delivery systems and dosage forms include its low aqueous solubility as well as its poor UV-, pH- and temperature-dependent stability. The purpose of this article is to discuss the mechanism of action, therapeutic effect and physicochemical properties of resveratrol and to present recent technological approaches designed to improve its stability, bioavailability and therapeutic efficiency.

Eco-Physiological Traits and Phenylpropanoid Profiling on Potted Vitis vinifera L. cv Pinot Noir Subjected to Ascophyllum nodosum Treatments under Post-Veraison Low Water Availability

In Mediterranean regions, extreme weather conditions during the growing season may alter grapevine physiology and metabolism, thus modifying the quality of wines. The objective of this study was to investigate the effects of Ascophyllum nodosum treatments on plant physiology and berry metabolism in Vitis vinifera exposed to water stress. The experiment was performed on potted vines subjected to two irrigation regimes (well-watered, WW, and water stressed, WS) both associated with A. nodosum treatments (SWE), compared with control plants (CTRL). Gas exchanges, chlorophyll fluorescence, and water relations were monitored on SWE and CTRL leaves, both in WW and WS vines at three times. Moreover, the quantification of secondary metabolites and their partitioning were performed in berry skins. Plants treated with A. nodosum extract showed higher photosynthesis and stomatal conductance than CTRL in both irrigation regimes and maintained a better plant hydraulic conductivity at the end of the sampling period. In addition, secondary metabolites in berry skins and their partitioning were significantly affected by the treatments in both irrigation regimes. Our results suggest that foliar application of A. nodosum extract may help the acclimation of grapevines to post-veraison water stress, likely improving plant physiological and biochemical performances under environmental constraints.

Berry Quality of Grapevine under Water Stress as Affected by Rootstock–Scion Interactions through Gene Expression Regulation

Despite phenotypic plasticity that allows the adaptation to harsh environments, when vines experience severe abiotic stresses, they can suffer from metabolic damages affecting grape production and quality. Grafting is an affordable strategy to mitigate these negative consequences since the rootstock can increase the drought tolerance in the scion. This work explored the effects of pre-veraison water deficit on vines grafted on different rootstocks (Mgt 101-14 and 1103 Paulsen) to obtain physiological, biochemical, and molecular information about the influence on grape quality. Repeated measurements were carried out to assess vine physiology, production, technological maturity, and berry phenolic composition. qRT-PCRs were executed on berry skins at maturity to assess the expression levels of ten genes and five miRNAs involved in the phenylpropanoid pathway. Water stress caused significant alterations in grape technological maturity. The rootstock effect was not detected in primary metabolism while it was well defined in the accumulation of phenolic compounds in berries (such as anthocyanins). Finally, significant differences were identified in gene and miRNA expression between water-stressed and well-watered vines. In conclusion, the response to water stress can be modulated by rootstocks, which mainly act by regulating secondary metabolism, especially in grapes.

A Sense of Place: Transcriptomics Identifies Environmental Signatures in Cabernet Sauvignon Berry Skins in the Late Stages of Ripening.

Background Grape berry ripening is influenced by climate, the main component of the “terroir” of a place. Light and temperature are major factors in the vineyard that affect berry development and fruit metabolite composition. Results To better understand the effect of “place” on berry ripening, transcript abundances in Cabernet Sauvignon berries grown in Bordeaux were compared to those in Reno during the late stages of berry development at similar berry sugar levels (19 to 26 °Brix, total soluble solids (TSS)). Day lengths were similar in both locations but day temperatures were warmer and night temperatures were cooler in Reno. TSS was lower in Bordeaux berries compared to Reno at maturity levels considered optimum for harvest. RNA-seq analysis identified 4,455 differentially expressed genes (DEGs) between Bordeaux and Reno grape skins at 22°Brix. Top DEG gene ontology categories involved response to stimulus (1464 genes), biosynthesis (1260 genes) and response to stress (834 genes). Some DEGS included genes encoding terpene synthases, cell wall enzymes, kinases, transporters, transcription factors and photoreceptors. Most circadian clock genes had higher transcript abundance in Bordeaux. The plant temperature sensor phytochrome B was linked with Reveille 1 expression, which is part of the circadian clock output pathway that affects seed dormancy. Bordeaux berries had higher transcript abundance with DEGs associated with seed dormancy, light, auxin, ethylene signaling, powdery mildew infection, phenylpropanoid, carotenoid and terpenoid metabolism, whereas Reno berries were enriched with DEGs involved in water deprivation, cold response, ABA signaling and Fe homeostasis. Conclusions Transcript abundance profiles in the berry skins at maturity were highly dynamic. RNA-seq analysis identified a common core set of ripening genes that do not depend on rootstock, vineyard management, plant age, soil and climatic conditions. Most DEGs could be associated with different environmental conditions that affected the berries in the two locations and may be potentially controlled in different ways by the vinegrower to adjust final berry composition and reach a desired result. Temperature, light, water status and fungal infection were identified to be some of the most influential factors that affected differential gene expression and the quality trait pathways associated with them.