New hardy apple scab resistant selections for cider and juice production

Abstract
Five hardy scab resistant selections ( 12166, 10625, SJC658, 13323, SJC7811-1 ) were put in replicated trials along with four standard cultivars ( Yarlington Mill, Golden Russet, McIntosh Summerland, Makamik ) to evaluate their potational for cider production. A taste panel consisting of 6 certified commission judges evaluated the cider samples. The cider was evaluated for aroma and taste with an emphasis on flavour and taste-related components e.g. fruit intensity, appeal, acid and tannin levels. Of all the genotypes tested, ciders made from ‘Yarlington Mill’, ‘12166’, and ‘10625’ were ranked the best followed by ‘Golden Russet and ‘McIntosh Summerland’.

Introduction

Apples are one of the leading deciduous fruit in Canada. The major part of the production is consumed fresh, and a large part of it is processed. On average, the blended apples have a ratio of sugar:acid of 15 :1 (g/L), which makes them suitable for juice and cider making. Some varieties, like ‘Golden Delicious’, are poor in acid content (a ratio of 20 :1), but the taste and the high yield of its juice help making this variety a good one for processing (De Groof, J., 1987). A mixture of different cultivars is often used to produce a higher quality cider. Emerson recommended the use of a mixture composed of 10% high acidity ciders, 50-60% medium acidity ciders, 30-40% ciders rich in soluble solids, and 5% ciders abundant in tannins (Emerson, 1983). Downing (1989) states that specifying which apples make the best cider is difficult, and that blending has always been an important step in controlling the uniformity of a finished product. The French and English have spent considerable time and effort cultivating cider apples that possess a high tannin and sugar content, while at the same time being relatively low in acid. Although leading countries in cider-making have specific apple selections meeting specific requirements for the different types of cider produced, in Quebec no attention was paid to genotypes specific for cider production. Traditionally, apples that could not be consumed fresh were processed into juice and cider. The cider produced from these apples had to be made from a blend of juices of different apple varieties, since varieties like McIntosh resulted in slightly unpleasant flavours when used alone (MacGregor et al., 1970).The objectives of this study were to measure and assess the various quality characteristics associated with apple cider from chosen apple selection compare to known cultivars presently used in commercial cider production.

 

Materials and Methods

Apples were picked at maturity from each of the following cultivar or selection : Yarlington Mill, McIntosh Summerland, Makamik, Golden Russet, SJC658, 13323, SJC7811-1, 12166 and 10625 and used for juice analysis and cider production.
Sample preparation for juice analysis
Analysis was done on the juice obtained from apple at harvest and also just before fermentation (72 days after storage). Juice produced from the entire apple including peel and core was mixed thoroughly and filtered under vacuum filtration, first through cotton wool and then through fast filter paper (AOAC, 1990). The filtered juice was immediately frozen and stored in at –20^oC. The pH of samples was measured using a glass electrode pH meter and total sugars were determined by the anthrone method of Fairbairn (1953). Total pectin substances were determined based on the method of Blumenkrantz and Asboe-Hansen (1973) for the quantitative determination of uronic acids. Total tannins and titratable acidity were determined based on the AOAC method (1990). Total soluble solids were analysed by refractometer as describe previously (Mattick and Moyer, 1983).

Sensory evaluation procedure
The Juice obtained from the above genotypes were fermented without adjusting for sugar, acid or tanin level. Samples were reviewed as to the characteristics that would affect a finished cider, but not as finished ciders themselves since no manipulation have been done on the juice before or during fermentation. The cider produced evaluated by taste panel consisted of 6 certified commission judges. The nine cider samples were evaluated first as to their aroma (intensity and appeal), then as to their taste, focusing on apparent flavors and taste related components like fruit intensity, appeal, acid and tannin level. An overall quality rank was also assigned to each cider after sensory evalution.

Results and discussion
pH and titratable acidity
Our results was similar to that of Labelle (1980) for the pH and titrable acidity of Yarlington Mill and Golden Russet that we used as standard (Table 1). In general, the level of titratable acidity in the genotypes after storage decreased but the cider pH showed slight increase from that measured after storage. Titratable acidity on the other hand decreased during the storage and was the least for cider.
Total sugars and soluble solids
Total sugars (TSS) and Ebrix was higher for 13323, SJC658, SJC7811-1 and Golde Russet (Table 1). These two characteristics seem to be positively correlated with TSS being slightly higher than EBrix. The genotypes with higher total juice sugar (Table 1) ranked lower for cider acidity with exception of the SJC7811-1 which had higher cider acidity.
Total pectic substances and total tannins
Genotype 12166, 13323 and Summerland McIntosh had higher level of pectic subtonics. It seems that the total pectic substances remain relatively the same before or after fermentation. Total levels of pectic substances may be of concern during cider manufacture with respect to haze formation. With regard to clarification of the juice, genotypes with low amounts of soluble pectin may require lower concentrations of clarifying enzymes to be used in their clarification, and/or milder temperatures and shorter times.
Of perhaps the most importance is the level of tannins present in the juice and in the cider itself. Labelle (1980) evaluated 40 different genotypes and found the tannin content of individual genotypes vary widely from 34-228 mg tannin/100ml. He reported average values of 106 for European genotypes and 69 for domestic genotypes. 13323, SJC7811-1, Makamic and Yarlingtion Mill had above 400 mg/100ml tannins and reported to have excessive tannins content (Table 1) and resulted in cider with excessive contents of tannins (Table 2). Golden Russet cider seemed to be in between the two groups.
Sensory analysis
Aroma was best in Yarlington Mill and McIntosh Summerland, but the taste appeal of the latter was poor. Acidity was more pronounced in SJC7811-1 and Makamik and less pronounced in Yarlington Mill and SJC658 than in the other genotypes. Tannin levels were excessive in 13323, SJC7811-1, and Makamik. Yarlington Mill was found to have very appealing apple flavours of ripe fruit, a good body, and a long, clean finish. It was rated first in an overall evaluation as reported by Mohr (1998), followed by 12166, 10625, and Golden Russet (Table1). Golden Russet has been highly rated by some Quebec cider-makers for the excellent flavour of the fermented product (Mohr, 1988). In our study, it was classed as fine to slightly better than ordinary as to taste, and it was found to have a good length of aftertaste. Selection 12166 was classed as a very good cider as it is, having very pleasant, soft apple flavours, and a long finish. Its aroma was reported to have moderate intensities of apple/pear aromas and floral notes. Selection 10625 was rated as fine to great. Its characteristics were comparable to those of 12166, and it was found to have focused apple flavours that intensify through a long persistent finish. Although McIntosh Summerland had intense aromatics and a floral, lush, complex, ‘fresh-picked’ odour, it had a low intensity apple flavour and thin watery taste characteristics. In a study determining the suitability of apples for cider production, the fruit of McIntosh scored poorly and was found one of the least suitable of 7 cultivars for cider production (Plocharski, 1990). Selections SJC658, 13323, and SJC7811-1 were classed as poor to ordinary, except for SJC7811-1 that was found to have very sweet apple/peach fruit flavors. Because of its excessive acid and tannin content, it was recommended that its major components be used only as a blending ingredient. Makamik also had brutal acid and tannin levels and very little apparent fruit. The possibility for it to be used as a blending ingredient, and only in very small amounts, was reported.Since there is no one apple genotype that is best for cider production, blending plays an important role in producing a cider with desired characteristics. For the purposes of blending, it is desirable to have on hand some ciders that possess high levels of acid as these can be used to add tartness to the cider. 10625, 12166, and SJC7811-1 are selection with high acid and may be suitable for this purpose.

Conclusion
Based on juice chemical analysis and sensory evaluation of the cider Yarlington Mill, and selection 12166 and 10625 ranked superior than the other. Makamik, 10625, 12166, and SJC7811-1, all seem to possess relatively high levels of acidity, and hence may be useful for blending purposes. Selection 13323 and Golden Russet appear to be useful as base juices due to their relatively high levels of sugar and low levels of acidity; whereas the genotypes Makamik, SJC7811-1, 13323, and Yarlington Mill appear to be suited to impart astringent properties to cider due to their total tannins content. Although cultivars and selections were not evaluated as finished ciders but as to the characteristics that would affect a finished cider, several samples were reported to make satisfactory single variety-ciders. Selection 12166 and 10625 appear to belong to that category and as such, appear to be promising in cider production and SJC658 seems to be suitable for juice due to its delicate clean ripe fruit aroma and stable light green yellow juice color. These selections are under futher evaluation for commercial cider production.

	AOAC. 1990. AOAC Official Methods of Analysis. 15th ed. AOAC Inc, Virginia.
	Beech, F.W., and J.G. Garr. 1977. Cider and perry. In Economic Microbiology :Vol.VI, Alcoholic beverages, ed. A.H.Rose, 139-313. Acdemic Press, London.
	Blumenkrantztz, N. and Absoe-Hansen, G. 1973. New method for quantitative determination of uronic acids. Anal. Biochem. 54 :484.
	De Groof, J. 1987. Qualité des fruits pour la fabrication de jus, de vins et de cidre. Le Fruit Belge 418 : 101-104.
	Downing, D.L. 1989. Pp. 169-188 in Processed Apple Products, D.L.Downing (ed.). Van Nostrand Reinhold, New York.
	Emerson, F. H. 1983. Apple cider production. Mich. Sta. Hort. Soc. Ann. Rep. 113 : 131-140.
	Fairbairn, N.J. 1953. A modified anthrone reagent. Chem. Ind. 72 :88.
	Hoo, A.F. & McLellan, M.R. 1987. The contributing effect of apple pectin on the freezing point depression of apple juice concentrates. J.Food Sci.52 :484.
	Labelle, R.L. 1980. Apple cultivars tested as naturally fermented cider at Geneva, Memo, New York State Agricultural Experiment Station, Geneva, New York.
	MacGregor, D. R., J. A. Ruck, and J. F. Bowen. 1970. Home preparation of juices, wines, and cider. Canada Department of Agriculture. Publ. 1406.
	Mattick, L.R., and J.C. Moyer. 1983. Composition of apple juice. J. Assoc. Off. Anal. Chem. 66(5) :1251-1255.
	Mohr, W. P. 1988. Apple cultivars for juice and cider production. Agriculture Canada Technical Bull. 1988-6E, Smithfield Technical Bull. no 7.
	Plocharski, W., W. Lenartowicz, J. Zbroszczyk, D. Kruczy½ ska. 1990. The suitability of apples for processing. I. Quality of fresh fruit of selected cultivars and their suitability for cider production. Fruit Sci. Reports 17 : 41-50.
	Proulx, A., and L. Nichols. 1980. Sweet and Hard Cider. Garden Way Publishing, Charlotte, VT.