The controversial relationship between chitosan and the microorganisms involved in the production of fermented beverages

Chitosan is a promising antimicrobial agent available in the beverage industry, because it ensures the control of a wide range of spoilage microorganisms. As chitosan does not alter the characteristics of fermented beverages, it is nowadays widely employed in the wine sector. In this work, an exhaustive chemical characterization of 12 commercial chitosans was performed in accordance with the OIV methods. These analyses made it possible to confirm or determine the animal or fungal origin of the 12 samples. Furthermore, ionic chromatography coupled with an amperometric detector (IC-PAD) confirmed peculiar polysaccharide profiles for fungal and animal-derived chitosans. The antimicrobial activity of chitosans was evaluated against the microorganisms involved in beverage fermentation or capable spoil wine, beer and cider. Chitosans were tested in static and stirred conditions, in a synthetic medium that reproduces fermented beverage conditions, to discriminate against the physical settling of cells and their specific antimicrobial activity. Moreover, the activity of the soluble portion of chitosan was checked by inoculating microorganisms in the media after chitosans removal. The results highlighted the different sensitivity of microorganisms to chitosans, allowing selective control of spoilage agents. However, the yeast and bacteria involved in fermentation were damaged by chitosan, and the synthetic media treated with this molecule showed a less fermentative aptitude. These results suggest that chitosan is a promising tool in fermented beverage production, but an in-depth study of the biochemical interaction between chitosan and food microorganisms is necessar

Atypical ageing defect in Pinot Blanc wines: a comparison between organic and conventional production management systems

Atypical ageing (ATA) is an aroma defect that occurs in white wines and entails a loss of varietal aromas as well as scents of wet mop, shoe polish and dish rag. 2-Aminoacetophenone (2AAP) - a degradation product of indole-3-acetic acid (IAA) - has been described as the main odour-active compound and chemical marker responsible for this off-flavour. A stress reaction in the vineyard triggered by climatic, pedological and viticultural factors can ultimately cause ATA development in wines and remarkably affect wine quality. The aim of this research was to investigate the influence of three grapevine management systems on the occurrence of ATA. The experiments were carried out on Pinot Blanc grape samples from vines cultivated using one conventional and two organic approaches. The management systems mainly differed for the fertilisation regime and the weed control

High-density balsamic vinegar: application of stable isotope ratio analysis to determine watering down

Balsamic vinegar of Modena (ABM) is a product obtained from concentrated grape must with the addition of wine vinegar. It can be adulterated with the addition of exogenous water. The official method EN16466-3, based on the analysis of the stable isotope ratio δ18O of the water, is not applicable to ABM with high density (above 1.20 at 20 °C). In this work, for the first time, the official method was modified, providing for a prior dilution of the sample and applying a correction of the data in order to eliminate the isotopic contribution of the diluent, whereupon the within- and between-day standard deviations of repeatability (Sr) were estimated. Considering the limit values of δ18O for vinegar and concentrated must, the threshold limit of δ18O, below which the ABM product can be considered adulterated, has been identified

White rot fungal impact on the evolution of simple phenols during decay of silver fir wood by UHPLC‐HQOMS

6openInternationalItalian coauthor/editorIntroduction Silver fir (Abies alba Mill.) is one of the most valuable conifer wood species in Europe. Among the main opportunistic pathogens that cause root and butt rot on silver fir are Armillaria ostoyae and Heterobasidion abietinum. Due to the different enzymatic pools of these wood-decay fungi, different strategies in metabolizing the phenols were available. Objective This work explores the changes in phenolic compounds during silver fir wood degradation. Methodology Phenols were analyzed before and after fungus inoculation in silver fir macerated wood after 2, 4 and 6 months. All samples were analyzed using high-performance liquid chromatography coupled to a hybrid quadrupole-orbitrap mass spectrometer. Results Thirteen compounds, including simple phenols, alkylphenyl alcohols, hydroxybenzoketones, hydroxycinnamaldehydes, hydroxybenzaldehydes, hydroxyphenylacetic acids, hydroxycinnamic acids, hydroxybenzoic acids and hydroxycoumarins, were detected. Pyrocatechol, coniferyl alcohol, acetovanillone, vanillin, benzoic acid, 4-hydroxybenzoic acid and vanillic acid contents decreased during the degradation process. Methyl vanillate, ferulic acid and p-coumaric were initially produced and then degraded. Scopoletin was accumulated. Pyrocatechol, acetovanillone and methyl vanillate were found for the first time in both degrading and non-degrading wood of silver fir. Conclusions Despite differences in the enzymatic pool, both fungi caused a significant decrease in the amounts of phenolic compounds with the accumulation of the only scopoletin. Principal component analysis revealed an initial differentiation between the degradation activity of the two fungal species during degradation, but similar phenolic contents at the end of wood degradation.openDi Lella, Stefania; La Porta, Nicola; Tognetti, Roberto; Lombardi, Fabio; Nardin, Tiziana; Larcher, RobertoDi Lella, S.; La Porta, N.; Tognetti, R.; Lombardi, F.; Nardin, T.; Larcher, R

Stable Isotope Ratio Analysis for authentication of natural antioxidant cannabidiol (CBD) from Cannabis sativa

Cannabidiol (CBD) is a non-psychoactive cannabinoid of Cannabis sativa that exhibits several beneficial pharmacological effects, including anti-inflammatory and antioxidant properties. The molecule can be obtained via extraction from the plant or through a biosynthetic route. The two products have both advantages and disadvantages, thus necessitating the development of methods capable of distinguishing between the two products. In this study, for the first time, the analysis of the stable isotope ratios of oxygen and hydrogen demonstrated high efficiency in the discrimination of CBD of a totally natural origin from that obtained through chemical synthesis. Considering a probability level of 95%, it was possible to identify threshold values for δ2H and δ18O of the totally natural CBD of −215‰ and +23.4‰, respectively. Higher values may indicate a non-entirely natural origin of CBD (i.e., a biosynthetic molecule)

Authentication and geographical characterisation of Italian grape musts through glucose and fructose carbon isotopic ratios determined by LC-IRMS

The authenticity of grape musts is normally checked through a time-consuming stable isotopic analysis of carbon (δ13C) after fermentation and distillation by following the official OIV MA AS-312-06 method. In this study, the alternative use of a technique based on δ13C isotopic analysis of the major sugars of the grape must by liquid chromatography coupled with isotope ratio mass spectrometry (LC-IRMS) is provided. It allows not only the detection of the fraudulent addition to grape must of exogenous glucose and fructose deriving from C4 plants but also the characterisation of it based on its geographical origin. In order to discriminate between musts from different areas of Italy, a preliminary dataset was considered; the δ13C isotopic ratios of glucose and fructose of around 100 authentic samples were analysed. The two analysed parameters, ranging from -29.8‱ to -21.9‱, are well correlated (R2 = 0.7802) and the northern regions showed significantly more negative δ13C values for both sugars than the rest of the datase

In berry distribution and extraction of thiol precursors in Gew\ufcrztraminer.

The so-called varietal thiols are an interesting technological class of compounds that contributes to the "tropical" notes of wine. The factors governing the formation of their precursors and the conversion to the corresponding free forms are still discussed (Thibon et al. 2016) but, technologically speaking, the precursor availability is a prerequisite. Several data are present in the literature regarding Sauvignon Blanc (SB), while fewer deal with Gew\ufcrztraminer (GWT; Dubordieu and Tominaga 2009; Roland 2010a & b; Concejero et al., 2014), a variety native to Tramin, in South-Tyrol (Italy). For this reason, we investigated the concentration of 3-S-glutathionylhexan-1-ol (GSH-3MH) and 3-S-cysteinylhexan-1-ol (Cys-3MH) in GWT as regards: (1) the distribution between marks and juice in samples processed at a semi-industrial scale, in comparison with SB samples having similar \ub0Brix and pressing yield; (2) the effect of pre-fermentation skin-contact protocols, also used along with commercial enzymes to favour extractions from skin; (3) the fractioning during pressing on industrial-scale. Thiol precursors were analysed according to Larcher et al. (2013). GWT skins are characterised by a higher content in precursors compared to SB\u2019s at the same pressing yield, while this difference is turned upside down in juice. Pre-fermentation skin-contact significantly increased thiol precursors' concentration while the impact of the enzymes was not significant. Around 30% of total precursors are contained in the pressing fraction corresponding to the final 5% of the juice

Energy consumption prediction using people dynamics derived from cellular network data

Energy efficiency is a key challenge for building sustainable societies. Due to growing populations, increasing incomes and the industrialization of developing countries, the world primary energy consumption is expected to increase annually by 1.6%. This scenario raises issues related to the increasing scarcity of natural resources, the accelerating pollution of the environment, and the looming threat of global climate change. In this paper we introduce a new and original approach to predict next week energy consumption based on human dynamics analysis derived out of the anonymized and aggregated telecom data, which is processed from GSM network call data records (CDRs). We introduce an original problem statement, analyze regularities of the source data, provide insight on the original feature extraction method and discuss peculiarities of the regression models applicable for this big data problem. The proposed solution could act on energy producers/distributors as an essential aid to smart meters data for making better decisions in reducing total primary energy consumption by limiting energy production when the demand is not predicted, reducing energy distribution costs by efficient buy-side planning in time and providing insights for peak load planning in geographic space.Telecom Italia SpASET Distribuzione Sp

Simultaneous yeast–bacteria inoculum. A feasible solution for the management of oenological fermentation in red must with low nitrogen content

The simultaneous inoculum of yeasts and bacteria is a feasible solution for improving fermentation in wines with a harsh chemical composition, capable of inhibiting microbial activity. Considering the risk of wine spoilage due to lactic bacteria, co-inoculum is suggested in white wines with a low pH. However, climate change has also caused problems in achieving malolactic fermentation in red wines, due to the high concentration of ethanol and the low nutrient content. In this work, 5 pairs of commercial oenological starters were tested in simultaneous fermentation, using 4 red musts with a low nitrogen content, and compared with a traditional winemaking process. The simultaneous inoculum caused a slowdown in the activity of yeasts, although no problems in the accomplishment of alcoholic fermentations were observed. More reliable malolactic fermentation was performed in the co-inoculum trials, while, in traditional winemaking, some failures in the degradation of malic acid were observed. Microbiological analyses agreed with these observations. No differences were found in yeast density during alcoholic fermentation, demonstrating the absence of negative interaction between the yeast and the bacteria. However, simultaneous fermentation is not without risks; the highest increases of acetic acid were noted in the co-inoculum trials. The addition of yeast and bacteria to must with a serious lack of nutrients would appear to be a promising alternative to traditional fermentation; however, careful control of the chemical composition of must is mandatory to obtain reliable microbiological activity in the first stages of winemaking