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Bating

Purpose

Further loosening and peptising of the fibre texture of the skin andelimination of alkali-swelling with the aid of specific enzymes.

Enzymes in bating agents

Enzymes are biological catalysts that accelerate the reactions without

themselves being modified. Enzymes, which act specifically on proteins,are called proteases.

The following proteases are used as bating agents:1. Pancreas proteases (trypsin)2. Mould fungus proteases3. Bacteria proteases

Bating agents with pancreas proteases (mainly used) develop their opti-mum effect in slightly alkaline pH range (8.0 8.5).

Composition:Enzymes, wood flour as carrier substance, ammonium salts, neutral saltsas buffering and deliming agents.

Bating agents with mould fungus proteases develop their best effect atpH 3.5 5.0, and bating agents with bacteria proteases at pH 6.0 7.2.The buffering substances in these bating agents are among others sulfi-tes and bisulfites.Commercial bating agents may contain a mixture of all three types of

proteases.

Influencing the bating effect

Temperature: The rate of enzymatic reaction increases with risingtemperature.

Bating temperature used in practice: 30 37 C.Higher temperatures cause damage to the skin material.

Neutral salt content: Higher concentrations may reduce or inactivate thebating effect.

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Rating of bating agents

The enzyme value is the number of enzyme units in 1 g bating agent. Oneenzyme unit has the fermentative capacity to digest 1.725 mg casein.

Enzyme value = LVUEnzyme unit = LVU x 1.725

The enzyme unit is determined according to Lhlein-Volhard by allowingthe bating agent to act upon an alkaline casein solution. Undigestedcasein is precipitated with hydrochloric acid and sodium sulfate. Thealkali consumption in re-titration is a direct measure of the enzymatic

effectiveness of the bating agent.

This titration method was recently supplemented by a photometricmethod with trinitrobenzene sulfonic acid (Tegewa method). Almost allliberated amino groups are also detected after hydrolysis by proteolyticenzymes.

Pancreas-based bating agents mainly used in practice:1. Weak bating agents = 500 1000 LVU

(technical leather, harness leather)2. Medium strong bating agents = 1000 1500 LVU

(upper leather, lining leather, fancy leather)3. Strong bating agents = 1500 2000 LVU

(glove, clothing leather)

BASF bating agents

Basozym C 10 Bating agent based on pancreatic enzymes foruse on all types of leather.Activity ca. 1000 LVU/g.

Basozym CS 10 Special enzyme preparation for opening upsmall skins and fur skins in acid media.Activity ca. 900 LVU/g.

Basozym 1000 Universal bating agent for all types of raw stockand all types of leather. Activity ca. 1000 LVU/g.

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