Optimizing a Method for Measuring Firmness of Chinese Cabbage (Brassica rapa) and Comparing Textural Characteristics among Cultivars

Abstract

In order to optimize a method to determine the firmness of Chinese cabbage, hardness of midrib tissues was examined based on their chronological order of emergence. Texture measurement using volodkevich bite jaws gave a consistent and highest regression (r 2 = 0.85) between firmness and the order of leaf emergence, while blade set, cylinder probe, and crisp fracture support rig showed a lower coefficient of determination. Thickness of midrib tissue within an individual head from 16 cultivars of Chinese cabbage was positively correlated with the order of emergence, becoming thinner toward inner leaves. Mean thickness of midrib tissue from the head ranged from 7.74 mm for 'CR-shingshing' and 9.28 mm for 'Norangyeorum'. The covariance of leaf thickness within a head was highly cultivar-dependent, ranging from 23.6% for 'Chihili' and 5.8% for 'Bulam'. Firmness of the midrib tissue, defined as maximum peak height per tissue thickness, became higher from outer to inner leaves, showing 2 nd order of regression. Mean firmness of the midrib tissue from individual head varied from 1.58 N for 'Rangno' to 3.46 N for 'CR-shingshing'. The 10 th or 11 th leaf brought the best correlation coefficient (r = 0.81) between firmness of an individual leaf and the mean firmness of the entire leaves in a head, suggesting a reliable and rapid method to estimate the firmness of a head in lieu of examining all leaves in the head. The relationship between firmness of midrib tissue and dry mass (r = 0.70**) as well as cell wall content (r = 0.58*) of the head were positively correlated. Results obtained from the present study suggested that a new method to determine midrib firmness would enable to clarify the relationship between textural quality of fresh Chinese cabbage and their processed product, 'Kimchi'. It will also be important to apply this method to screen textural quality of various genotypes under breeding programs.

Physicochemical Quality Changes in Chinese Cabbage with Storage Period and Temperature: A Review

“…Gonaengjeeyureum) (Yang et al, 1993a). Firmness is exhibited differently in different Chinese cabbage varieties, the general trend being that the inner leaf is firmer, whereas mid-rib firmness decreases within the same head (Jeong et al, 2012). Another study on the Chinese cabbage cultivars 'CR-Nongshim' and 'Ryouckgwang' reported that storage temperature did not significantly affect firmness (Eum et al, 2013b).…”

Effect of Combined Pallet Unit MAP and Plasma Treatment for Extending the Freshness of Spring Kimchi Cabbage

“…따라서 대부분의 처리구에서의 색도 변화는 저장 초기에 비하여 저장 3주부터는 값의 변화가 있는 것으로 나타났지만, 저장 기간과 처리구 간에 증가와 감소를 반복하는 등 뚜렷한 경향을 보이지는 않았다. 경도 국제식품규격에 의하면 김치의 품질은 정상적인 색상, 맛 그리고 조직감을 가지고 있어야 하며, 이중 조직감은 '적당히 단단 하고 아삭아삭하고 씹는 맛이 있어야 한다'라고 표기되어 있다(Jeong et al, 2012). 본 실험에 사용된 cylinder probe는 조직을 파쇄하는데 소요되는 힘의 최고치로 조직의 질김 정도나 물렁하거나 유연한 정도를 나타낸다.…”