비파(Eriobotrya japonica Lindley) 착즙액 첨가가 요구르트 균주의 산 생성 및 증식에 미치는 영향

This experiment was carried out to investigate the effect of loquat (Eriobotrya japonica Lindley) extract on the acid production and growth of lactic culture in reconstituted skim milk. The supplementation level of loquat extract to reconstituted skim milk was 10%, 15% and 20%. Reconstituted skim milk containing loquat extract was fermented by single of mixed culture of Streptococcus thermophilus, Lactobacillus acidophilus and Lactobacillus casei. General compositions of loquat extract, changes of viable cell count, pH and titratable acidity during fermentation were determined. Chemical compositions of loquat extract were 91.5% moisture, 0.2% crude ash, 8.6°Brix soluble sugar, 0.34% total acid, and 4.11 in pH. Supplementation of loquat extract stimulated acid production and growth of lactic acid bacteria. Among supplementation levels, a group that was fermented by a single culture of Str. thermophilus with 10% loquat extract was shown the highest viable cell count (2.10×10^(9) CFU/mL) at 12 hours after inoculation. When loquat extract was added to reconstituted skim milk at the level of 10%, all mixed cultures of lactic acid bacteria showed higher acid production and the number of viable cell count than 3 kinds of single cultures. Especially, the growth of mixed culture of Str. thermophilus and Lac. acidophilus was promoted by the addition of 10% loquat extract. Therefore, it was suggested to manufacture the yoghurt with the addition of 10% loquat extract and the inoculation of mixed culture of Str. thermophilus and Lac. acidophilus for on the stimulation of growth of the lactic culture.