Influence of different yeast strains on fermentation behaviour, physico-chemical and sensory qualities of plum wine

Natural Product Radiance, Vol. 8(4), 2009, pp.445-451 Research Paper Influence of different yeast strains on fermentation behaviour, physico-chemical and sensory qualities of plum wine Introduction Amongst the stone fruits, plum (Prunus salicina Linn., Hindi- Alubukhara) is an important fruit grown throughout the temperate regions of the world. In India, two types of plum are grown; the European plums (P. domestica Linn.) are grown at higher elevations while the Japanese VK Joshi *, Somesh Sharma and Mutum Preema Devi Department of Postharvest Technology Dr. Y S Parmar University of Horticulture and Forestry Nauni, Solan 173 230, Himachal Pradesh, India *Correspondent author, E-mail: vkjoshipht@rediffmail.com;winevkj@yahoo.com Received 21 April 2009; Accepted 26 June 2009 Abstract Effect of different yeast strains of Saccharomyces cerevisiae var. ellipsoideus, viz. UCD 505, UCD 595, UCD 522, W and Tablet Strains on the enological and sensory characteristics of plum wines was determined. Different yeast strains influenced the physico-chemical characteristics of the wines produced to a variable extent. All the yeasts fermented plum musts to dryness (sugar content of 0.5% or low). The higher rate of fermentation was shown by 595, tablet and W yeast strain compared to 505 and 522. Out of various strains, UCD 595 gave the highest efficiency along with higher ethanol yield. The Tablet strain produced lowest ethanol in wine. The wine made with UCD 595 had higher titratable acidity and lower yields of aldehyde compared to other yeasts. The highest methanol content was found in wine fermented with the yeast strain Tablet while the lowest content of methanol was produced by strain W. The principal component analysis (PCA) of the physico-chemical characteristics showed that the parameters like aldehyde, methanol and tannins separated the yeasts into two groups, viz. one group had W and Tablet strain while the second had UCD 505, UCD 595 and UCD 522 ; TSS, acidity, ph, total sugar, ethanol and colour did not contribute to separation of yeasts. Sensory evaluation scores of different wines revealed that the must fermented with the yeast strain UCD 595 and W had higher scores for colour, taste, flavour and overall acceptability. However, PCA of sensory analysis showed grouping of yeasts different than that of physico-chemical characteristics; W, Tablet and UCD 595 made one group while remaining second group. All the wines except that fermented by UCD 522 were of commercial acceptability. It is concluded that the use of appropriate yeast strain for the preparation of plum (Prunus salicina Linn.) wine is very important along with other vinification practices as it influenced the chemical and sensorial quality of wine. Keywords: Plum, Prunus salicina, Alubukhara, Wine, Ethanol, Principal Component Analysis, Sensory evaluation, Yeast, Saccharomyces. IPC code; Int. cl. 8 C12G 1/00 plums (P. salicina Linn.) are cultivated in the lower regions and sub-mountainous areas of the country. In India, plum is grown in an area of 14000 ha with a total production of 80,000 tonnes per year. In mid-hills of Himachal Pradesh, Jammu and Kashmir, hills of Uttar Pradesh, Meghalaya and Nilgiri Hills of Tamil Nadu, the fruit is grown commercially. Himachal Pradesh produces 9373 tonnes of plum annually in an area of 8396 ha 1-3. Plum is a highly perishable fruit with a shelf-life of 3-4 days at ambient temperature and 1-2 weeks in cold storage. Most of the production goes waste due to poor market demand and less processing avenues. Heaps of plum rotting in plum orchards, due to lack of non-utilization, can be seen during the production season. The main commercial cultivar plum, Santa Rosa is highly acidic and its utilization in processing is limited for use as an ingredient in preparation of mixed fruit jam and some non-alcoholic beverages. Production of alcoholic beverages from this fruit is a profitable alternative available to utilize the crop. Wines are nutritious drinks unlike distilled liquors. In the recent past, specific health benefits to the consumption of wine especially in the prevention of coronary hearth diseases (CHD) to particular phenolic antioxidant compounds that are found in wine have been ascribed. The compounds found in wine include flavon-3-ols, the flavanols and anthocyanins. Plum fruit is also a rich source of phenolic compounds and the red colour of the fruit is mostly contributed by anthocyanins 4-8. Some investigations have been carried out for preparation of alcoholic Vol 8(4) July-August 2009 445

beverages from plum including wine, vermouth, sparkling wine and brandy 9-15. However, the potential of plum in wine making has not been fully realized in the country though wine and brandy is prepared commercially from this fruits in several countries of the world 8,13. Production of plum wine with phenolic compounds would be quite attractive especially when it is the cheapest raw material among the fruits. To prepare wine, fermentation is performed either naturally without inoculation or by inoculating fruit juice with selected yeasts. The role of Saccharomyces cerevisiae in wine making has been described earlier and selected strains of S. cerevisiae have given definitely better results than the spontaneous fermentation. The composition and quality of wine has been found to be related closely with the yeast used. Further, different yeast strains have different effects on the fermentation pattern, physico-chemical and sensory quality of wines 16. In our earlier works, we have reported the effect of cultivar, type of preservatives, the mineral composition of plum wine and biological deacidification 10,17-19. In the present studies, impact of the different yeast strains on the fermentability and quality of wine has been investigated. Materials and Methods Fruit and wine yeast culture The fruits of plum cultivar Santa Rosa were employed in the study. The enzyme pectin esterase pectinol was obtained from M/s Triton Food Industry, Mysuru. The wine yeast cultures, viz. UCD 595, UCD 522, UCD 505, W and Tablet 446 were employed in the study. Three standard wine yeast, viz. 595, 522 and 505 were obtained by the courtesy of Dr R E Kunkee, Head Department of Enology and Viticulture, California. The Tablet yeast was commercially obtained from Australia used for home wine making while W was an isolate from our own laboratory. Cane sugar was used to raise the TSS of the must. The chemicals employed in analysis were of analytical grade. Fermentation The plum musts were prepared by diluting the pulp in 1:1 ratio with water. The TSS of the must was raised to 24ºB. To the must 100 ppm of SO 2 in the form of KMS and 0.5% pectinol was added. Fermentations were performed in 10 litre glass vessels containing 6 litre of plum must at 25 o C. Fermentations were initiated by the addition of yeast inoculums of all the five yeast strains grown in separate plum pulp diluted appropriately. The respective cultures were added at the rate of 5% (v/v). The fermentations were conducted as per the details given earlier 12. During fermentation, the rate (ºB/24h) was measured by recording fall in degree Brix every day. After completion of fermentation, the wines were racked and after proper clarification, it was bottled keeping 2.5cm headspace. The bottled wines were pasteurized at 62.5ºC for 15 min. The wines were analyzed after maturation for a year in the bottles and before evaluation, the wines were blended to 12 o B by addition of sugar syrup to make acceptable acid /sugar/alcohol blend as reported earlier 20. It was allowed to mix properly and then evaluation for sensory analysis was carried out. Analyses Physico-chemical analysis: The wines prepared were analysed for TSS ( o B), titratable acidity, ethanol, ph, total sugars, aldehyde, tannins, colour and methanol. TSS was measured using Erma hand refractometer (0-32 o B) and corrected for the temperature variation 21. Titratable acidity (as per malic acid) was estimated by titrating a known aliquot of sample against N/10 NaOH solution. The ph was measured with ELTOP 3030 ph meter, while Lovibond tintometer (model E) was used to measure the colour of wines 22. The colour was expressed in Red, Yellow and Blue colour units. The total sugars were estimated by Lane and Eynon s volumetric method 21. Ethyl alcohol in the finished wines was determined by the colorimetric 23. The total phenols (tannins) in different wines were measured by the Folin-Ciocalteau procedure 24. Aldehyde in different wines was estimated as per the prescribed method 8. The methanol content was analyzed by Gas Liquid Chromatograph, equipped with FID with packed Propack Q column. Column and injector temperatures were 130 and 220 o C, respectively and the flow rate of carrier N 2 Gas was 30ml/min. The analysis was performed after optimizing the separation of mixture of ethanol and methanol, appropriately. Sensory evaluation: The sensory evaluation of wines of different treatments was conducted by a trained panel of 10 judges. Each judge was given a set of wines separately in isolated booths and provided with a glass of fresh water to rinse their mouth before tasting the next sample. Each sample was evaluated for various quality attributes, viz. colour, Natural Product Radiance

consistency, aroma, overall acceptability, etc. as per the prescribed performa 8. Judges were asked to rate the samples on a prescribed sensory evaluation performa with earlier stated attributes 8, 25. The wine was also evaluated by judges on a scale of 20 for each attribute for analysis by PCA. The means were employed for analysis, using the statistical package detailed later on. Statistical analysis: The data were analyzed by PCA using a computer programmed PCA Date 26. The results of sampling cases and species were plotted simultaneously in a graph to interpret the results. In the data, physico-chemical parameters were used as sampling units and the yeast as species. The sensory analyses data were simultaneously analyzed by PCA and plotted in a graph. Results and Discussion The physico-chemical characteristics (Table 1) of the wines prepared with different yeast strains clearly show that TSS of all the wines ranged from 7.2 to 7.6 B and all the wines were fermented to dryness as the residual concentrations of total sugars of all the wines was less than 0.5%. Although the TSS of the wines was quite high, the residual sugar content was very low. It is because of the fact that TSS includes all soluble components including sugar. The rate of fermentation of all the yeasts showed that the Tablet and W yeast strains gave the highest reduction in TSS and UCD 505/522 gave the lowest. All the yeast strains recorded rate of fermentation higher than 1.6 and strains UCD 595, W and Tablet had same rate of fermentation. Difference in tintometer colour units of wines fermented by different yeasts was also observed. The titratable acidity of the wines prepared with different yeasts ranged between 0.7 to 0.9% (Table 1) which was virtually comparable in all the wines. Thus, yeasts did not influence the acid production in the wines and is desirable. The yeast strain suitable for wine production should have high fermentabiltiy, tolerance to ethanol, sedimentation property and no effect on titratable acidity. Further, the ph of wines was according to their respective acidities. The Fig. 1 reveals that the strains UCD 595 and UCD 522 produced higher ethanol (12.50% and 12.03%, respectively) than other strains, which is of great interest to produce high quality wine. The amount of ethanol produced by the yeast is desirable character and from this point of view UCD 595 proved to be the best. Further, all the five strains (UCD 505, UCD 595, W, Tablet and Table 1: Effect of different wine yeast strains on the physico-chemical characteristics of plum wine Characteristics Yeast strains 505 595 W Tablet 522 Total Soluble Solids ( o B) 7.6 7.2 7.2 7.2 7.6 Titratable acidity (% malic acid) 0.8 0.9 0.8 0.7 0.8 ph 2.8 2.9 2.8 2.9 3.0 Total sugar (%) 0.4 0.5 0.3 0.3 0.4 Rate of fermentation (RF) 1.64 1.68 1.68 1.68 1.64 ( o B/24h) Tintometer colour (Units) Red 4.8 3.8 6.8 3.8 4.8 Yellow 8.0 7.0 5.4 8.7 7.5 Blue 0.1 0.1 0.1 0.1 0.1 Quality (%) 14 12 10 8 6 4 2 0 505 595 W Tab 522 Yeast Cultures Fig.1 : Effect of different yeast cultures on ethanol content of plum wine Vol 8(4) July-August 2009 447

UCD 522) consumed practically all the initial sugar, one of the most important criteria for selecting yeast for wine making. The results shown in Fig. 2 also reveal that strain UCD 595 had the highest fermentation efficiency followed by strain UCD 522. However, Tablet strain gave minimum fermentation efficiency. Although, the yeast fermented wines to almost dryness their rate of fermentation were different. This is due to the fact that different yeast strains have differences in production of ethanol and other byproducts because of that there are differences in the fermentation efficiency of the yeast. UCD 595 gave the highest efficiency which is desirable also. It is clearly evident from Fig. 3 that W yeast strain produced the maximum aldehyde content and strain 522 produced the minimum aldehyde content in the plum wines. Production of low level aldehyde is a desirable characteristic of a wine yeast. Generally, production of aldehyde indicates incomplete alcoholic fermentation or oxidation of alcohol 8. The wine fermented by W had the highest tannins while that of UCD 522 the lowest. Although, the yeasts are not known to produce /synthesize any phenolic compound yet difference in tannins content vis-à-vis yeast strains can be attributed to precipitation of tannins by the components released by the yeasts in the fermenting musts. The content of methanol in different wines was comparable. The highest amount of methanol was produced by Tablet (Fig. 3), while the lowest was recorded in wines fermented with W yeast strain. Production of methanol is an undesirable characteristic of wine yeast, the strains of S. cerevisiae generally do not produce Quantity (mg/l) Fermentation efficiency (%) 350 300 250 200 150 100 50 90 80 70 60 50 40 30 20 10 0 505 595 W Tab 522 Yeast cultures Fig.2 : Fermentation efficiency of different yeast strains employed in plum wine preparation 0 505 595 W Tab 522 Yeast cultures Fig.3 : Effect of different yeast cultures on aldehyde, tannin and methanol contents of plum wine methanol but the hydrolysis of pectin present in fruits might have contributed to production of methanol 8. Nevertheless, the amount of methanol in all the wines was too small to be significant. The summary of PCA of the physico-chemical analysis (Table 2) shows that the variations in the data have been accounted for 99% and has virtually been defined by first two components. The PCA analysis of the data of physico-chemical Aldehyde Tannin Methanol characteristics further revealed that out of various parameters studied TSS, titratable acidity, ph, total sugars, ethanol and colour units did not contribute much to the separation of yeast. Aldehyde, tannin and methanol contents have contributed towards separation of yeasts into two groups; group I comprising of W and Tablet yeast strains while 595, 522, 505 constituted group II. Thus, based on PCA of the physico-chemical 448 Natural Product Radiance

Table 2: Summary of Eigen analysis of physico-chemical characteristics data by Principal Component Analysis Species Eigen Per cent Accumulated (Yeast Value of Trace per cent of Trace strains) 1 4.564 91.3 91.3 2 0.429 8.6 99.9 3 0.007 0.1 100 4 0.000 0.0 100 5 0.000 0.0 100 Table 3: Effect of different wine yeast strains on the sensory characteristics of fermented plum wine Attributes Yeast strains 522 595 505 W Tablet Appearance (2) 1.6 1.9 1.7 1.7 1.8 Colour (4) 1.8 1.6 1.8 1.5 1.6 Aroma (2) 2.5 3.4 3.0 3.4 3.4 Volatile acidity (2) 1.0 1.7 1.7 1.7 1.7 Total acidity (2) 1.0 1.6 1.3 1.6 1.6 Sweetness (1) 0.4 0.6 0.5 0.6 0.6 Body (1) 0.5 0.7 0.6 0.7 0.7 Flavour (2) 1.0 1.7 0.8 1.5 1.6 Bitterness (1) 0.4 0.7 0.5 0.7 0.5 Astringency (1) 0.3 0.8 0.4 0.8 0.8 Overall impression (2) 1.3 1.7 1.3 1.7 1.7 Total 11.8 16.4 13.6 15.9 16.0 Table 4: Summary of Eigen analysis of sensory analysis data by Principal Component Analysis (PCA) Species Eigen Value Per cent of Trace Accumulated per cent of Trace 1 2.660 53.2 53.2 2 1.509 30.2 83.4 3 0.424 8.5 91.9 4 0.357 7.1 99.0 5 0.050 1.0 100.0 characteristics, it is clear that yeast UCD 595, 522 and 505 have many similar characteristics. In an earlier study also it was found that S. cerevisiae strains contribute to enological and sensorial characteristics of wine produced 16. The application of PCA to the data showed that the wines fermented with different yeast strains were well differentiated. The variable that contributed to the first component was defined by volatile acidity. From the results (Table 3) it is evident that wines fermented with UCD 595 strain obtained higher scores for appearance, aroma, body and flavour while those prepared with Tablet and W yeast strains received higher scores for total acidity, sweetness, acidity and overall impression. It is concluded that plum wines prepared by using strain UCD 595, W and Tablet have better sensory quality compared to that produced from UCD 522 and UCD 505. The summary of eigen analysis of data of sensory analysis (Table 4) showed that first four components have contributed towards variations in the data. The projection of sensory analysis data (Fig. 4) analyzed by PCA showed that appearance, colour, volatile acidity, overall impression, total acidity have contributed towards separation of yeasts into two groups, group I comprising of W, Tablet and UCD 595 and group II comprising of UCD 505 and UCD 522. Astringency, bitterness, body and sweetness apparently have not been affected by the type of yeast. Out of various characteristics; appearance, colour, volatile acidity, titratable acidity are related with PCA I positively while sweetness, bitterness, body are closely associated with PCA II. Aroma, flavour and astringency have been weekly defined by PCA II. Vol 8(4) July-August 2009 449

Sweetness Astringency Bitterness Body Flavour Total acidity Overall impression W Tab Volatile acidity 595 Apperance 8. Amerine MA, Berg HW, Kunkee RE, Ough CS, Singleton VL and Webb AD, Technology of Wine Making, 4th edn., AVI, Westport, CT, 1980. 9. Vyas KK and Joshi VK, Plum wine making: Standardization of methodology, Indian Food Pack, 1982, 36(5), 80-85. 10. Joshi VK, Attri BL and Mahajan BVC, Studies on preparation and evaluation of vermouth from plum, J Food Sci Technol, 1991, 28, 138. Aroma 522 Colour 505 11. Joshi VK and Sharma SK, Comparative fermentation behaviour of physico-chemical and sensory characteristics of wine as affected by types of preservatives, Chem Microbiol Technol Labsm (CMTL), 1995, 17(1/2), 45-53. Fig.4: Projection of sensory characteristics of plum wines fermented by different yeasts strains in planes defined by PC-1 and PC-2 12. Joshi VK, Fruit Wines, Directorate of Extension Education, Dr YS Parmar Univ. Hort Forestry, Nauni- Solan, HP, India, 1995, pp.151-152. Compared to physico-chemical characteristic the response of sensory analyses is little different and it can be attributed to the effect of maturation which might have affected the sensory characteristics of wine. Conclusion It can be concluded that various yeast strains influenced the fermentation behaviour, physico-chemical and sensory characteristics of the resulting wines. Thus, use of appropriate yeast strain for the preparation of plum wine is very important along with the other vinification practices. References 1. FAO STAT, http:/faostat.org/default/567, 2008 2. Bhutani VP and Joshi VK, Plums, In: Handbook of Fruit Science and Technology, 450 Cultivation, Storage and Processing, DK Salunkhe and SS Kadam (eds), Marcel Dekker, USA, 1995, pp. 243-296. 3. Anonymous, Department of Horticulture, HP Nav Bahar, Shimla, 2008. 4. Bission LF, Butzke CE and Ebbler SE, The role of moderate ethanol consumption on health and human nutrition, Am J Enol Vitic, 1995, 46(4), 449-462. 5. Stockley CS, Therapeutic value of wine: A clinical and scientific prospective, In: Handbook of enology, VK Joshi (ed), Asia Tech Publ. Co., New Delhi, 2009. 6. Frankeil EN, Kanner J et al, Inhibition of oxidation of human low density lipoproteins by phenolic substances in red wines, Lancet, 1993, 341, 454-457. 7. Wang HG, Cao H and Prior RL, Oxygen radical absorbing capacity of anthocyanins, J Agric Food Chem, 1997, 45, 304-309. 13. Tesevic V, Nikicevic N, Jovanevic A, Djokovic, D, Vajistic L, Vuckovic I and Bonic M, Volatile components from old Plum Brandies, Food Technol Biotechnol, 2005, 43(4), 367-377. 14. Joshi VK, Sandhu DK and Thakur NS, Fruit based alcoholic beverages,in: Biotechnology: Food Fermentation (Microbiology, Biochemistry and Technology), Vol II, VK Joshi and Ashok Pandey (eds), Educational Publishers & Distributors, New Delhi, 1999, pp.647-744. 15. Bhardwaj JC, Joshi VK and Kaushal BBL, Value addition of plum by fermentation into sparkling wine - influence of sodium benzoate concentration, and yeast immobilization on fermentation behaviour of plum must by Schizo pombe yeast, J S Chauhan, SD Sharma, RC Sharma, AS Rehalia and K Kumar (eds), Acta Hortic, II, 2005, 533-540. 16. Vilanova M, Masneuf-Pomarede I and Dobourdieu D, Influence of Saccharomyces cerevisiae strains on general composition Natural Product Radiance

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