Assessment of metallic contaminants in grinded millet using domestic grinding machine

J.K Odusote,I.I Ahmed,S Abdulkareem,K.A Akande,G.A Soliu

doi:10.4314/njtd.v14i1.2

Abstract

In this study, the quantity of metallic contaminants extracted from grinded millet was evaluated. The millet was grinded in three different forms; wet, paste, and dry forms for up to 3 minutes using locally fabricated grinding machine with cast grinding discs. Separate grinding discs were used for different millet forms, while the same quantity of millet, 1 kg, was used throughout the experiments. The millet was soaked for 24 hours before grinding in order to obtain wet and paste forms of the millet. Metallic contaminants were carefully extracted from the grinded millet using magnetic bed along with sedimentation and decantation. The extracted materials were then quantified to ascertain the food form that produces the highest amount of metallic contaminants. Also, the wear rate of the grinding disc was also determined with respect to the grinding time. The results show that the wet form has the highest amount of metallic contaminants of about 1.397 g followed by the paste form with 1.075 g. The dry form has the least value corresponding to 0.945 g. The grain sizes of the metallic contaminants were calculated to be 12.095 nm for the wet form, 8.056 nm for paste form while the dry form has the smallest grain size of 3.124 nm. The results revealed that metallic contaminants are always contained in grinded food processed with local grinding discs. Thus, materials with better wear resistance should be selected for production of grinding discs to be used for food processing.Keywords: Millet, Metallic contaminants, Quantification, Magnetic extraction, Sedimentation and Health hazards

Highlights

Food processing is a common practice because most food crops are hardly consumed in raw form
From the study, it can be concluded that the millet grinded using locally fabricated grinding machine with cast iron grinding discs contained metallic contaminants
The amount of the contaminants in the grinded millets was found to be dependent on the form of the grinded form

Summary

Introduction

Food processing is a common practice because most food crops are hardly consumed in raw form These food crops are usually processed through cleaning, drying, milling, grinding, etc, in order to make them suitable for consumption or for other domestic and commercial purposes (Yahaya et al, 2012, Kirk et al, 1991). Based on these, when grinding discs are being in used during grinding of food item, shear force is applied, leading to surface wearing of the discs. This is the main cause of iron filings and metallic inclusions in our grinded food items (Bello et al, 2007, Cabrera et al, 2003, Llobet et al, 2003). Common contaminants in processed (grinded) food item are most likely from the metal components of the mill, the soil, the paints used as coat for machine components, bushings, bearings, grease and

Methods

Results

Conclusion