CASPAR VAN LEEUWEN, PATRICK ZWAMBORN,
WILLEM VAN RIJSWIJK
Center For Testmaterials BV
Stoomloggerweg 11, 3133 KT Vlaardingen, The Netherlands

Abstract

*Part I was published in H&PC Today, Vol. 11(4) July/August 2016, pag. 61-66
In recent years, a new generation of enzymes has been introduced to the detergent market to target fatty stains, which keep making an interesting market since they are consumer-relevant. To help remove fatty stains, improved Lipases have been developed and introduced to the market.
Recently, we have received an increasing number of enquiries about the fat and the dye levels used in our range of commercial test-materials. Current fat and dye levels in the commercial test-materials are concentrations determined in earlier studies based on previous generations of lipase enzymes. In the past, the lipase effect on test-materials was relatively low, so it was quite difficult to determine what would be the optimum levels of fats and dyes in our test-materials. The new lipases might yield more measurable effects on test-materials. This would enable us to investigate the effects of fat levels and dye levels on test-material sensitivity to lipase to a much greater extent, hence offer an improved range of test-materials to our customers. For publication reasons this article is intentionally split into three different papers.
Part one addresses the method, dye information, results and conclusions of research hypotheses 1 and 2 (the new generation of lipase is one of the enzymes to consider when it comes to improved wash performance; Fatty stains are more responsive to Lipase activity when they are washed with powder detergent than with liquid detergent).
Part two (this part) considers the hypotheses 3 and 4 (fatty stains on knitted cotton are more responsive to lipase activity than fatty stains on woven cotton; Reduced dye levels in test-materials lead to a better Dynamic Range).
Part three revolves around the remaining results and conclusions regarding hypotheses 5 and 6.
(Reduced fat levels in test-materials lead to a better Dynamic Range; Different groups of fatty stains react differently to lipase activity).

INTRODUCTION

This research investigates the responsiveness of test-materials to the new generation of lipase enzymes. It also explores several “recipe” changes which might improve responsiveness to lipases.

A range of standardized test-materials and circular stains was selected on the basis of previous research results and knowledge gained through many years of experience.
A total of 74 test-materials were examined, including 23 readily available commercial test-materials and 51 new experimental test-materials which were especially developed for this research.

These test-materials comprise five groups of comparable fatty stains which are both common in reality and often used as test-materials. The research investigated which standardized test-materials and circular stains had the best responsiveness to lipases within these five groups:

• Vegetable oils/fats
• Butter fat
• Beef fat
• Lard
• Lipstick

Responsiveness to lipase was quantified by measuring the ∆ Reflectance (∆R) at 460nm for (a) no, (b) low, (c) medium and (d) high dosages of lipase, tested at 25 ...