An Eco-Friendly Proposal by Integrating Chromatographic Fingerprinting and Multivariate Control Chart in a Non-Target Analysis to Evaluate Grape Juices from Different Farming Practices

A potential eco-friendly method without organic solvents is presented by integrating a chromatographic fingerprint and multivariate control chart based on Q residuals to differentiate grape juices from different farming practices. The sample preparation was only water dilution, and the mobile phase was water acidified with sulfuric acid, which can be readily neutralized before its disposal. The proposed method is shown to be a simple way to distinguish between organic and non-organic grape juices in a non-target way, successfully evaluating an external validation data set, where organic and non-organic samples were correctly assigned. Through the chromatographic profile, it is possible to suggest that one of the species responsible for this distinction may be from the anthocyanins class.

Effect of Different Processing Conditions on Bioactive Compounds of Selected Grape Varieties

Bioactive compounds in grapes vary in terms of cultivar and processing conditions. Raw juice and treated grape juices from locally grown Israel blue and locally available, imported, Red Globe and Michele Palieri varieties in Sri Lanka were used for the analysis. Grape juices were subjected to different processing conditions such as pasteurization and pectinase enzyme treatment. Total Monomeric Anthocyanin content (TAC), Total Phenolic Content (TPC), and antioxidant activity were analyzed. Compared to the imported grape varieties, the locally grown, pectinase enzyme-treated Israel blue grape juice with 2% pectinase enzyme concentration, 40 0C incubation temperature, and 2 hours incubation time, under dark condition had the significantly highest values (p < 0.05) for TAC at 177.03±4.15 mg/L of malvidin-3-O-glucoside (M3G), TPC at 527.07 ± 3.55 mg/L of Gallic acid equivalents and antioxidant activity in terms of DPPH radical scavenging assay with IC50 value at 7.05±0.35 mg/mL Gallic acid equivalents and ABTS radical scavenging assay with IC50 value at 0.31±0.01 mg/mL of Trolox equivalents. TAC, TPC, and antioxidant activity of three grape varieties showed the highest values in pectinase enzyme-treated grape juice which was followed by raw juice and the pasteurized juice respectively. This research has taken an approach to enhance the bioactivity of grape juices via pectinase enzyme treatment and evaluate the suitability of locally grown Israel blue grape variety in Sri Lanka to form as a functional beverage to meet nutritional and health requirements.

Development and Validation of a Simple RP-HPLC-PDA Method for Determination of 18 Polyphenols in Grape Juice and Red Wine

According to the trend of a healthy eating awareness trend, having a potential benefit on human health, some polyphenols like flavonoids, resveratrol, hydroxy-stilbenes, and phenolic acids are in the spotlight. Grapes, and one of the most widespread grape product wine; are among the best sources of these polyphenols. In this study, a highly specific, susceptible, and easy chromatographic method was brought out and validated to determine 18 polyphenols in grape and red wines. For this aim, an HPLC-PDA was used, and the separation was accomplished on an RP-ODS4 column. The method comprised of a mobile gradient phase consisting of A solution (acetic acid in water, pH 2.00) and a mixture of the solution A – acetonitrile (20:80, v/v), at a flow rate of 1.0 ml/min, and PDA detection was carried out at 260,280, 320, and 360 nm. According to the results, it can be said that the program indicated good linearity over the range of 1-40 mg L−1 of phenolics with r2>0.99. The recovery of the 18 phenolics ranges from 83.17% to 119.88% at red wines and 88.20% to 117.83% at grape juices. The method is well precise, with the relative standard deviation (RSD) of the average concentration of the phenolic compounds are ranges from 1.22% to 2.02% at red wines and 1.01% to 2.56% at grape juices.

Native Yeasts and Lactic Acid Bacteria Isolated from Spontaneous Fermentation of Seven Grape Cultivars from the Maule Region (Chile)

Grapes are a source of native yeasts and lactic acid bacteria (LAB); however, the microbial make up is dependent on the grape cultivar and the regional growth conditions. Therefore, the aim of this study was to characterize the yeast and LAB in seven grape cultivars cultivated in Chile. Grape juices were fermented at 25 °C for 7 days. Samples were collected to analyze sugar, organic acids, and ethanol. Microbial evolution was measured with culture-dependent and molecular approaches. Then, a native isolated Candida oleophila was selected for further sequential fermentations with Saccharomyces cerevisiae. The grape cultivars in the Maule showed a diversity of non-Saccharomyces yeasts, with a greater diversity observed at the beginning of the fermentation. However, species from the Hansenasporia, Metschnikowia, Torulaspora, Lachancea, and Candida genera were detected after 7 days, suggesting tolerance to environments rich in ethanol, capability may be associated to the terroir studied, which is characterized by torrid weather and antique and traditional vineyards. The alcoholic fermentation negatively impacted the LAB population, and after 7 days only Leuconostoc mesenteroides was isolated. In the sequential fermentations, C. oleophila was able to produce fermented grape juices with <1.5 g/L glucose, 12.5% (v/v) alcohol, and low concentrations of malic (<1.00 g/L) and succinic (2.05 g/L) acids, while acetic acid reached values >0.3 (g/L). To our knowledge this is the first time C. oleophila has been reported as a potential starter culture for wine production. However, more studies are necessary to fully characterize the potential of C. oleophila on wine attributes.

Amylase Based Clarification of Apple, Orange and Grape Juice

Amylases are starch-degrading enzymes produced by many bacteria, plants, fungi and animals. It has found tremendous application in industry. One of its applications is in fruit industry wherein amylases are used to clarify fruit juices and reduce its viscosity. In fruits, high amount of starch is present which resulted in increased viscosity of the prepared juices. This may also lead to settling of juice at bottom. Amylases act on starch component and degrade it. In the current study, amylase from B. licheniformis was used for the clarification of apple, orange and grape juices. Total suspended solids, viscosity and total acidity was found to decrease with increasing amylase concentration. The results revealed that after amylase treatment the color, texture and flavor of juices were also improved.

The Combined Use of Lachancea thermotolerans and Lactiplantibacillus plantarum (former Lactobacillus plantarum) in Wine Technology

Most commercialized red wines are produced through alcoholic fermentation performed by yeasts of the Saccharomyces genus, and a second fermentation performed by lactic bacteria of the Oenococus oeni species once the first is completely finished. However, the classical process can suffer complications, of which the risks can increase in grape juices with high contents of sugar and pH. Due to climate change, these situations are becoming more common in the winemaking industry. The main risks in those scenarios are alcoholic-fermentation stops or sluggish and undesirable bacteria development while alcoholic fermentation is not finished yet and wine still contains residual sugars. The study propose a novel alternative that offers a solution or reduces the risk of those scenarios while increasing acidity, which is another serious problem of warm viticulture regions. The alternative consists of the combined use of Lachancea thermotolerans to reduce the pH of musts that suffer from a lack of acidity, Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) to achieve malic acid stability during the first stages of alcoholic fermentation, and Saccharomyces bayanus to complete the alcoholic fermentation in difficult wines of high potential alcohol degree of over 15% (v/v). The new proposed biotechnology produced wines with higher final concentrations in lactic acid, glycerol, color intensity, ethyl lactate and 2-phenyl ethyl acetate in 2.39 g/L, 0.52 g/L, 21%, 48% and 37% respectively than the classical methodology where Saccharomyces genus performs alcoholic fermentation and later Oenococus oeni performs malolactic fermentation. Additionally, the new alternative produced wines with lower concentration in ethanol, pH, acetic acid, ethyl acetate, diacetyl and 1-propanol in 0.37% (v/v), 0.26, 0.08 g/L, 22%, 69% and 28% respectively than the classic method.

Physicochemical and sensory properties of grape juices produced from different cultivars and extraction systems

The objective of the present study was to evaluate grape juices from different cultivars obtained by two different technologies: steam juicer system (S1) and enzymatic system (S2). The beverages were evaluated for physicochemical and sensory characteristics and their adequacy to the identity and quality standards of whole grape juice. Experiments were carried out in the 2018 and 2019 harvests with the grape cultivars BRS Rúbea (RUB), BRS Cora (COR), BRS Violeta (VIO), BRS Carmem (CAR), BRS Magna (MAG), Bordô (BOR), Isabel (ISA), Isabel Precoce (IP), Concord (CON), Concord Clone 30 (C30) and SCS 421 Paulina (SCSP). Treatments followed factorial design (cultivars x extraction system). S1 resulted in juices with lower soluble solids content; on average, a reduction of 3.12 °Brix in 2018 and 2.30 °Brix compared with the original content in grapes. Among S1 juices, only VIO and MAG in 2018, and VIO and CAR in 2019 achieved the minimum value of soluble solids (14 °Brix) established by the Brazilian legislation. Juices of SCSP and CON in 2018 and C30, CON and RUB in 2019 presented values lower than 14 °Brix, independent of the extraction system. S2 juices were characterized by higher values of total acidity, soluble solids, reducing sugars, anthocyanins, global impression, and equilibrium, as well as lower values of lightness for most of the cultivars.