Low-Cost Investment with High Quality Performance. Bleaching Earths for Phosphorus Reduction in the Low-Temperature Bleaching Process of Rapeseed Oil.

Barbara Łaska-Zieja,Ewelina Wojciechowska,Gniewko Niedbała,Wojciech Golimowski,Damian Marcinkowski

doi:10.3390/foods9050603

Abstract

Rapeseed oils are a valuable component of the diet. Mostly, there are refined oils deprived of valuable nutrients in the market, hence in recent times cold-pressed and unrefined oils have been available and popular among consumers. However, the low yield of this oil makes this product expensive. The aim of the study was to analyse the effectiveness of phosphorus reduction in crude oils, cold- and hot-pressed in the low-temperature bleaching process. Eight market-available bleaching earths was compared. The effectiveness of 90% was found with 2% (m/m) of Kerolite with hydrated magnesium silicate. An increase in the share of earths to 4% (m/m) resulted in the effectiveness of phosphorus reduction >90% in seven out of eight analysed cases. Bentonite activated with acid with the lowest MgO content was characterised by low efficiency <64%. The research shows that the effectiveness of phosphorus reduction was significantly affected by the composition of earths applied in the bleaching process at ambient temperature. The results of research confirm the high effectiveness of the process as it is not necessary to heat up the oil before the bleaching process. This method is recommended for existing and new industrial plant for two-stage rapeseed oil pressing.

Highlights

Rapeseed oil is widely produced and consumed in Europe and is the third most important vegetable oil after palm and soybean oils in the world [1,2]
Our research focused on the preparation of rapeseed containing lowest possible phosphorus using focused on the preparation of rapeseed oils containing the lowest possible phosphorus content using bleaching earths
The analysis of the results proved that the bleaching earth P2 had the lowest effectiveness of phosphorus reduction

Summary

Introduction

Rapeseed oil is widely produced and consumed in Europe and is the third most important vegetable oil after palm and soybean oils in the world [1,2]. In the market there are available pressed, unrefined oils containing valuable nutrients. Rapeseed oil has a lower concentration of saturated fatty acids (5−10%), higher content of monounsaturated fatty acids (44−75%), and moderate content of α-linolenic acid (9−13%) [3]. The production of cold-pressed oil is inefficient, while the production of hot-pressed oil results in its dark colour and the presence of phospholipids that are harmful to health. The solution is oil refining, as a result both phospholipids and valuable nutrients are removed. Phosphorus is removed from the oil in the degumming process

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Conclusion