Modulation of Aroma and Sensory Properties of Prokupac Wines by a Bacillus-based Preparation Applied to Grapes Prior to Harvest

Abstract

Modern viticulture requires the replacement of hazardous agrochemicals with eco-friendly, bio-based products such as microbial preparations that enhance grape and wine quality while protecting the grapevine from pest and disease attacks. This study investigated the effects of a commercially available Bacillusbased preparation on the volatile and sensory properties of wines made from Vitis vinifera, cv. Prokupac grapes. Three different concentrations of preparation based on Bacillus subtilis Ch-13 were applied to grapevines two weeks prior to harvest. The total soluble solids in the grapes was affected by the application of B. subtilis Ch-1 and the alcohol content of the wine made from these grapes was greater. Wines made from the B. subtilis Ch-13-treated grapes showed an average increase in total phenolic compounds of about 27%, compared to the wine made from the untreated control grapes. The colour intensity of wines from the treated grapes, independently of the concentration, was higher by more than 30% than for the wine from the control grape sample. The B. subtilis Ch-13 treatment also affected the content of 3-methyl-1-butanol, ethyl decanoate and ethyl octanoate in the wine, at about 35%, 40% and 20%, respectively. The latter compounds are responsible for floral and fruity aromas. Generally, wines made from the treated grapes showed similar sensorial characteristics but scored better overall than the control. Principal component analysis showed a clear differentiation between wine made from the control and that from the B. subtilis Ch-13-treated grapes. The results suggest that the application of B. subtilis Ch-13 to grapevines two weeks prior to harvest has a positive effect on wine quality.

Fermentative Potential of Native Yeast Candida famata for Prokupac Grape Must Fermentation

“…Further, it was shown that yeast strain used for the fermentation did not significantly influence total wine acidity, while significantly lower volatile acidity was detected in both samples fermented with C. famata (pure or sequential) compared to the control sample. The total (titratable) and volatile acidity for both samples produced with C. famata isolate were consistent with previously published results for the monovarietal Prokupac wines [20,22]. Beside the total acidity, it was proven that organic acid profile is strongly correlated with wine overall quality and sensory characteristics [38,39].…”

“…Prokupac is an autochthonous red grape variety characteristic for the central part of Serbia with long use in wine production [20]. Prokupac wine has unique phenolic profile with high content of anthocyanins, flavonols, flavon-3-ols monomers and hydroxybenzoic acid derivatives which contribute to expressive antioxidant activity [21,22].…”

“…Prokupac wine has unique phenolic profile with high content of anthocyanins, flavonols, flavon-3-ols monomers and hydroxybenzoic acid derivatives which contribute to expressive antioxidant activity [21,22]. Wine produced from this grape variety has been characterized as low in color intensity, but with a dominant red-berry and a discreet floral aroma described as linden, acacia and rose notes [20].…”

A Comparative Analysis of Microbe-Based Technologies Developed at ICAR-NBAIM Against Erysiphe necator Causing Powdery Mildew Disease in Grapes (Vitis vinifera L.)

“…Among them, Ampelomyces quisqualis, Trichoderma harzianum, T. asperellum, T. virens, Pythium oligandrum, Pseudozyma flocculosa, Bacillus subtilis, B. licheniformis, B. brevis, B. cereus, Pseudomonas fluorescens , and Streptomyces cacaoi were noteworthy (Rao et al, 2015 ; Damalas and Koutroubas, 2018 ; Thakur et al, 2020 ; Salimi and Hamedi, 2021 ). However, very few microbe-based products/technologies are available in the market for wider applicability in the Indian subcontinent and abroad to control grape powdery mildew in the organic viticulture (Compant et al, 2013 ; Moyer et al, 2016 ; Cangi et al, 2018 ; Malićanin et al, 2020 ). Due to a lack of information in the scientific literature on the availability and effectivity of microbial inoculants, agronomists and vine growers are often not aware of these new products and the impact they can have indirectly on the quality of grapes (Lu W. et al, 2020 ; Agbowuro et al, 2021 ; Steiner et al, 2021 ).…”