2 種の天然パン酵母の製パン特性に関する研究.

山田 密穂; 小泉 昌子; 峯木 眞知子; 藤森 文啓

Shirakamikodama yeast (S) and Hoshino natural yeast leaven (H) are the most widely known bread yeasts. However, little is known about their properties and effects on bread-making. This study examined the bread-making characteristics of S and H, using instant dry yeast (D) as a control. S contains only yeast; H contains yeast, flour, rice and koji and D contains yeast, vitamin C and emulsifier. Thus, several substances other than yeast affect bread-making. Additionally, all three yeasts were identified as Saccharomyces cerevisiae by sequencing the internal transcribed spacer region. Meanwhile, microscopic observation revealed differences in the shape and size of each yeast. The number of viable yeast cells per 1 g of product was approximately 1/10,000 less in H than in D and S. Analysis When the same number of viable yeast cells was used, H showed the fastest carbon dioxide generation rate (up to 460 min). Moreover, D produced the highest amount of carbon dioxide, while S and H generated similar amounts. Meanwhile, differences in volume, weight or specific volume were observed among breads prepared with an identical amount of viable yeast cells from each product. D and S produced the softest and hardest breads, respectively, while H resulted in bread with intermediate hardness. Histological analysis revealed differences in the shape of air bubbles and condition of air bubble films. These findings suggest that although bread-making with H requires a longer fermentation time, using the same number of H yeast cells as D and S can increase the fermentation time to a comparable level while ensuring the same quality. The findings also revealed that although S does not require seeding, it has the same number of viable yeast cells as D, resulting in bread with a similar level of puffing within the same fermentation time. However, although both yeasts were identified as S. cerevisiae, it remains unclear whether the differences in the amount of carbon dioxide generated, bread firmness and bubble state were due to mutations in the yeast genome sequence or changes in gene expression. Therefore, a detailed analysis is required in the future.

New Food Industry, 2022, Vol 64, Issue 12, p749

0547-0277

Academic Journal