Characterization of ginger proteases and their potential as a rennin replacement
Resource
J.Sci.Food Agric. 89: 1178-1185
Journal
Journal of the Science of Food and Agriculture
Journal Volume
89
Journal Issue
7
Pages
1178-1185
Date Issued
2009
Author(s)
Abstract
BACKGROUND: Ginger rhizome (Zingiber officinale Roscoe) contains ginger proteases and has proteolytic activity. Ginger proteases have been used for tenderizing meat but rarely for milk clotting. The purpose of this study was to purify ginger proteases and to research their biochemical characteristics. RESULTS: Themilk clotting activity (MCA) and proteolytic activity (PA) of the proteases was stable after storage at 4 °C for 24 h. TheMCA and PA of fresh ginger juicewith 0.2% L-ascorbic acid remained stable for 6 days at 4 °C. When under storage at-80 °C for 2 months, theMCA and PA of the fresh ginger juice and acetone precipitate were still high. Two peakswith protease activity were purified from a DEAE FF ion-exchange column; the specific activity (units mg-1 protein) of the MCA (MCSA) and PA (PSA) for the first peak was significantly higher than the second peak (P < 0.05). The protease activity of the ginger proteases was significantly inhibited by E-64, leupeptin, and iodoacetic acid. Zymography results showed that two protease fractions purified from ginger juice with 62 and 82 kDa had a higher PA against α- and β-casein than against κ-casein. CONCLUSION: The ascorbic acid addition significantly stabilized the MCA and PA of ginger proteases. The protease inhibition test suggested that ginger proteases belongedto the cysteine type.Thebiochemical characteristicsofgingerproteasedescribed in this paper can provide useful information formaking new milk curd products.
Type
journal article
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