Acid-Insoluble Ash

The common procedure usually adopted for the determination of acid insoluble ash is given below ... 

Procedure Place the ash, as described earlier, in a crucible, add 15 ml DW and 10 ml hydrochloric acid (- 11.5 N), cover with a watch-glass, boil for 10 minutes and allow to cool. Collect the insoluble matter on an ashless filtre paper, wash with hot DW until the filtrate is neutral, dry, ignite to dull redness, allow to cool in a desiccator and weigh. Repeat until the difference between two successive weighings is not more than 1 mg. Calculate the percentage of acid-insoluble ash with reference to the air-dried drug. 

Feedstock material and processed solids were analyzed for glucan, xylan, arabinan, and acetyl groups by quantitative acid hydrolysis according to standard methods (25). The acid-insoluble residue was considered as Klason lignin, after correction for the acid-insoluble ash (determined by igniting the contents at 575°C for 5 h). 

The specific quality indices are seed moisture, < 6% total ash, 7% acid-insoluble ash, 1.5% volatile oil, minimum 2% foreign organic matter, 2%. 

Saxena et al. (2004) established the quality standards of whole ajowan and ajowan powder. The whole and powdered forms of ajowan (dried fruits) being sold in Indian markets have been evaluated. The moisture content, organic extraneous matter, inorganic extraneous matter, damaged/ shrivelled/immature seeds and volatile oil content of whole ajowan and the moisture, total ash, acid-insoluble ash, non-volatile ether extract, crude fibre and volatile oil content of powdered ajowan are used as quality parameters. Agmark grade specifications of ajowan seed are given in Table 16.4. 

ASTA recommends a moisture limit of 10% in the whole spice. Ash and acid-insoluble ash should be no greater than 6 and 1%, respectively. Tables 18.6 and 18.7 show the chemical and physical specifications for the whole and ground spice, including the FDA DALs for the whole spice. 

ASTA suggest maximum moisture levels of 10%. Ash and acid-insoluble ash should be less than 10 and 2%, respectively. Tables 22.3 and 22.4 summarize the typical chemical and physical specifications, including the FDA s DAL, for whole celery and ground celery, respectively. 

Boil the ash obtained as directed under Ash (Total), below, with 25 mL of 2.7 N hydrochloric acid for 5 min, collect the insoluble matter on a tared, porous-bottom porcelain filter crucible or ashless filter, wash it with hot water, ignite to constant weight at 675° 25°, and weigh. Calculate the percent acid-insoluble ash from the weight of the sample taken. 

Acid-Insoluble Ash Determine as directed in the general method, Appendix EC. 

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