Application of thermal inactivation of enzymes during vitamin C analysis to study the influence of acidification, crushing and blanching on vitamin C stability in Broccoli (Brassica oleracea L var. italica)

作者：Munyaka Ann Wambui; Oey Indrawati; Van Loey Ann; Hendrickx Marc^*

来源：Food Chemistry, 2010, 120(2): 591-598.

DOI：10.1016/j.foodchem.2009.10.029

• L-ascorbic acid
• Dehydroascorbic acid
• Broccoli
• Blanching
• Acidification
• Crushing
• Enzymes

The effectiveness of heat inactivation of oxidative enzymes e.g., ascorbic acid oxidase (AAO) to stabilise vitamin C during extraction and analysis was evaluated. The influence of different sequences of performing treatments including acidification (pH 4.3 vs. pH 6.5), crushing, high temperature short time (90 degrees C/4 min-HTST) and low temperature long time (60 degrees C/40 min-LTLT)) blanching on vitamin C stability in broccoli florets and stalks was also investigated. Heat inactivation of enzymes prior to matrix disruption resulted in higher vitamin C values mainly in L-ascorbic acid (L-AA) form, while lack of enzyme inactivation resulted in high vitamin C losses resulting from conversion of L-AA to dehydroascorbic acid. Various treatments and their sequence of application influenced vitamin C stability as follows: (i) crushing prior to blanching reduced vitamin C stability and (ii) in the absence of heating, acidification increased vitamin C stability (iii) blanching prior to crushing resulted in higher vitamin C retention, with HTST blanching retaining more vitamin C than LTLT blanching.

• 出版日期2010-5-15