Quality tests
There are a number of other tests used in the industry, some of which are for specific herbs or spices. Some of the best-known and widely used are:
- Piperine levels. The test is specifically for peppers of the piper species. This involves extraction measurement of the characterising heat portion of the pepper the piperine content. After refluxing in alcohol to extract the piperine, absorbency is compared to a standard in a spectrophotometer at 342-345 nm.
- (ASTA) Colour values. This is a measurement of the extractable colour of products of the capsicum species and its principal use is a quality indicator for paprika. Extraction is in acetone over a 16 hour ambient extraction period and again the methodology is spectrophotometric against a standard at 460nm. The methodology was developed by the American Spice Trade Association and it is still often known as the ASTA colour value.
- Capsaicin content. Capsaicin is the pungent principle that gives heat to the capsicum species. Extraction of capsaicin is by re-fluxing with alcohol. The determination is by HPLC using acetonitrile/water as the carrier. It can be related to the Scoville test (see below).
- Scoville heat units. The Scoville heat unit is a measure of the heat levels (capsaicin content) of the capsicum species. It involves extraction of the capsaicin in alcohol and tasting of successively stronger dilutions in sugar syrup until the chillie heat is detected. It gives a compatible result to capsaicin content but obviates a need for sophisticated laboratory equipment. A trained tasting panel is required. (Scoville units divided by 150,000 = percent capsaicin.)
- Curcumin content. This is a test specific to the measurement of the extractive colour of turmeric. This is carried out by reflux extraction in acetone followed by measurement using a spectrophotometer at 415-425 nm.
Tags: quality, tests, herbs, spices, cooking