Quality Characteristics of Commercially Sold Bagels in Tokyo, Japan

Abstract

The texture of bagels sold in Japan varies considerably from hard to soft ; moreover, texture is an indication of bagel quality. However, studies evaluating the quality of commercially sold bagels in Japan are limited. Therefore, this study was conducted to examine the quality characteristics of commercially sold bagels in Tokyo and classify them based on their quality attributes. To achieve this, 12 bagels were purchased from five outlets in Tokyo and their moisture content, color, gas cell number, and area were analyzed. The results showed that the weight, specific volume, crust hardness, and crumb hardness of the bagels ranged from 6.34×10 g to 18.8×10 g, 1.78 cm³/g to 3.88 cm³/g, 0.94×10⁵ N/m² to 10.7×10⁵ N/m², and 1.01×10⁵ N/m² to 6.25×10⁵ N/m², respectively. The moisture content was low, ranging from 28.7% to 36.8%. Additionally, the gas cell number of the bagels ranged from 11.2 gas cells/cm² to 28.1 gas cells/cm² ; the gas cell number was significantly negatively correlated (r＝−0.801) with crumb hardness, indicating that crust ehardness was reduced with an increasing gas cell number. Principal component analysis showed that factors related to bagel swelling condition and crumb quality were clustered in the first principal component (PC1 ; contribution rate, 35.5%), whereas factors related to the apparent shape of bagels were clustered in PC2 (contribution rate, 24.6%). Factors related to crust quality were clustered in PC3 (contribution rate, 20.9%). Based on principal component analysis, the 12 samples were classified into five groups. Overall, our findings show that bagels sold in Tokyo vary in quality and texture, ranging from hard to soft. Additionally, as the number of bubbles in the crumb increased, the weight of the bagel decreased and texture became softer, suggesting that the weight of bagels can be used in texture determination.