| 摘要 |
<p>Periodic inspection of cooking fats and oils to determine their quality (free fatty acid content) during use, by testing the oil with an alkaline aq. soln. of an indicator or mixture of indicators, which has colour changes in the regions (a) just above neutral, pref. pH is approx. 7.6, (b) somewhat higher pH, pref. is approx. 8, (c) pref. just below neutral, esp. pH is approx. 6.</p> |
