D. Y. PATIL BIOTECHNOLOGY & BIOINFORMATICS INSTITUTE
Wine is an alcoholic juice made from any fermented fruit like cranberries, apples, blackberries, but customarily grapes are used. The production of wine from grapes is a biotechnological process in itself and winemaking is incomplete without the presence of enzymes. Apart from the enzymes derived from grapes, yeast & other microorganisms, commercial enzymes are prevalent in various stages of winemaking. These industrial enzymes provide quantitative, qualitative & processing advantages. The significant sources of enzymes for winemaking are Bacterial (Lactic Acid Bacteria), fungal (Botrytis cinereal) & yeast-based (S. cerevisiae). 80% of microbial sources contribute to an extended range of commercial enzymes. While designing a combination of commercial enzymes, scientists always look after the demands of each wine variety. Various microorganisms are made to grow on substrates under laboratory conditions to procure commercial enzymes.
The characteristics of the wine are due to the biotransformation reactions (a process by which a compound changes from one form to another), which are being catalyzed by enzymes. Commercial enzymes offer a collection of outcomes, from improved maceration (soaking grape skin in wine to obtain flavor & color) to sensory aspect. Major commercial enzymes applied in winemaking are:
1.) Pectinases – Cause depolymerization of cell wall & grape decomposition for improvement of clarification & filtration.
2.) Lipases – Decomposition of membrane lipids for enhancement of extraction & color stabilization.
3.) Glucanases – Catalyzes autolysis (breakdown of glucan), leading to release of mannoprotein for enhancing blooming of malolactic bacteria.
4.) Glycosidases – Hydrolysis of glycosidic bonds to portray organoleptic properties.
5.) Proteinases – Hydrolysis of peptide bonds, to eradicate heat-labile proteins & also works as an anti-foaming agent.
Genetic engineering made it easier for food scientists to produce desirable enzymes, as the technology involves the exploitation of single-celled organisms to obtain enzymes for commercial use. One of the biggest advantages is the shorter life cycles of microorganisms (majorly LAB & yeast), which allows rapid testing and understanding of the interactions between fusion of enzymes used in winemaking. This in turn provides a clearer picture of biocatalysts to estimate modifications for enzyme improvement.
One example where researchers used genetic engineering in winemaking is during secondary fermentation. Malolactic enzyme is responsible for decarboxylation of malate to lactate but LAB shows insufficiency in fulfilling the degradation of malic acid to lactic acid. This inadequacy leads to wine modification as well as the building-up of unwanted metabolites. Hence, scientists cloned the malolactic gene from Lactococcus lactis & accurately expressed it in Saccharomyces cerevisiae, but due to the inefficacy of S. cerevisiae to deliver malate; scientists surmounted this by simultaneous expression of malate permease (from Schizosaccharomyces pombe) with malolactic enzyme.
Since scientists can now formulate enzymes, to conquer industrial benefits before applying enzymology, the selection of enzymes is a must. A wrong choice may lead to undesirable flavor or it may mask the varietal aroma of grapes. Following are the basic steps involved in the production of commercial enzymes:
Feasibility assessment 🡪 Bioinformatics & Metagenetics 🡪 Cell Biology & Strain development 🡪 Trial Fermentation & Sampling 🡪 Product Analysis & Qualification 🡪 Process Development & Optimization 🡪 Fermentation & Scaling Up 🡪 Purification & Recovery.
Here are the few recent advances in commercial enzymes applied in the wine industry:
1.) Improved polysaccharide degradation.
2.) Immobilization of enzymes for different steps in winemaking (maceration, fermentation, clarification, wine stabilization & aging).
3.) Improved liberation of grape terpenoids with the help of glycosidases, glucanases, and arabinofuranosidases.
4.) Enhancement of protein stability & clarification with proteases.
5.) Improved liberation of varietal aroma.
In the past couple of decades, the wine industry has shown considerable progress in enzyme preparations. This has led to greater approaches in the quality of wine, allowing scientists to take a step ahead when it comes to supplementing endogenous enzymes with commercially produced ones. Still, the understanding of enzymatic interactions is in its early stages. The prime aspect for producing the finest wine is to underpin the optimal enzymatic activities & to cut down the inadmissible effects to nominal. The advances in enzymology hold great potential to overcome molecular-level challenges. It is time for you to uncork the bottle of wine which is not just filled with fruit-driven flavor but with intriguing science happening within!