Pectic Substance Degradation and Texture of Carrots as Affected by Pressurization

Authors

  • NORIKO (HYAKUMOTO) KATO,

    1. The authors are with the Dept. of Nutritional Science, Faculty of Health & Welfare Science, Okayama Prefectural Univ., 111 Kuboki, Soja, Okayama 719-11, Japan. Address in quiries to Michiko Fuchigami.
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  • AI TERAMOTO,

    1. The authors are with the Dept. of Nutritional Science, Faculty of Health & Welfare Science, Okayama Prefectural Univ., 111 Kuboki, Soja, Okayama 719-11, Japan. Address in quiries to Michiko Fuchigami.
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  • MICHIKO FUCHIGAMI

    1. The authors are with the Dept. of Nutritional Science, Faculty of Health & Welfare Science, Okayama Prefectural Univ., 111 Kuboki, Soja, Okayama 719-11, Japan. Address in quiries to Michiko Fuchigami.
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  • A part of this work was supported by the Grant-in Aid for Scientific Research (C) from the Ministry of Education, Science, Sports and Culture in Japan.

ABSTRACT

Heated pectin was degraded by transelimination (β-elimination) above pH 5 and by hydrolysis below pH 2, but pressurized pectin did not degrade. Thus cooked carrots decreased in firmness, but pressurized carrots did not. Pressurizing above 200 MPa slightly increased rupture strain. Galacturonic acid levels decreased in carrots cooked for 30 min. Total pectin in pressurized carrots was the same as in cooked for 3 min. However, with increased pressure, the amount of high methoxyl pectin in carrots decreased while low methoxyl pectin increased. Thus, the effects of pressurization on pectin degradation (transelimination) and texture of carrots were different from those of heating.

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