Quality changes in frozen Brussels sprouts during storage. I. Sensory characteristics and residual enzyme activities

Abstract

Sensory evaluation and quantitative analyses of catalase, peroxidase and lipoxygenase were performed in frozen Brussels sprouts during storage at three different temperatures. Within 6 weeks at -4°C all sensory attributes had reached the limit of acceptability , while peroxidase activity increased in the same period. At the end of this period catalase activity had increased strongly. Colour and flavour decreased slowly during 11 months storage at -9"C, while texture remained on a constant level. After 4 months at -9°C a slight catalase activity became detectable. At -18°C no detectable changes occurred during 1 1 months. Characterization of the preliminary blanching process in terms of residual activities of peroxidase and catalase remains possible after prolonged storage, provided microbial growth can be excluded.

Biochemical and colour changes of watercress (Nasturtium officinale R. Br.) during freezing and frozen storage

“…The decrease (comparing with the first storage day) was greater at lower temperatures, 79.5% at À30°C, 74.7% at À15°C and 71.2% at À7°C. Similarly results were noted by Steinbuch et al (1979) in Brussels sprouts. This activity reduction could be attributed to higher enzyme denaturation, as was referred by Gökmen et al (2005).…”

Quality changes in frozen Brussels sprouts during storage. II. Objective quality parameters: texture, colour, ascorbic acid content and microbiological growth

“…The results of colour measurements with the HunterLAB are shown in Table 1. There is a marked decrease in greenness ( --a ) with time and temperature, which is fully synchronous with the results of the measurements on whole product and also with the colour assessed sensorically (Steinbuch et al, 1979). Below a = 8, the colour was no longer acceptable to half the test panel.…”

“…Materials and sampling techniques are described in the first part of this publication (Steinbuch et al, 1979).…”

“…In the first part of this publication (Steinbuch et al, 1979), the sensory characteristics and the residual enzyme activities of frozen Brussels sprouts, stored at three different temperatures, were reported, and the importance of objective quality parameters was stressed. In this part, the behaviour of four objective quality parameters, measured during the same storage period, is reported.…”

“…The ascorbic acid content also has been investigated by several authors for its usefulness as a quality parameter (Dietrich, Huxsoll & Guadagni, 1970;Eheart & Odland, 1973;Abrams, 1975;Blegen & Rognerud, 1972;Pimm, 1973 ;Woyke & Makowski, 1968).…”