Preparation and Characterization of Microcrystalline Cellulose from Lucerne (Medicago sativa) Waste Fibers as Food Additive

One of the cellulose derivatives is microcrystalline cellulose (MCC), that is widely used in food and pharmaceutical industries as excipients, anti-caking agents, emulsifiers, binders, disintegrating agents, dispersants, emulsion stabilizers, thermal stabilizers and carriers for fast drying and tableting agents. In this study, MCC was prepared from dried Lucerne (alfalfa) waste fibers of which the pigments were already extracted as food colorants. This cheap and renewable raw material was converted to MCC by conventional methods including dewaxing, de-lignification, bleaching and acid hydrolysis. Commercial microcrystalline cellulose (Avicel PH-101) was used as reference compound for comparative studies. For characterization of prepared MCC, particle size analysis (PSA) was performed. The results of the particle size analysis showed mean particle size of the prepared sample was approximately 26 µm. Fourier Transform Infrared spectroscopy (FTIR) of prepared MCC showed similar spectra to that the commercial MCC. Thermogravimetric analysis (TGA) of the prepared MCC in comparison to that of the commercial MCC contain three main stages of weight changes. TGA behavior of both samples are matching together. In order to study the crystallin structure of the prepared MCC, X-ray diffraction (XRD) analysis was carried out. The XRD pattern from prepared MCC was similar to that of commercial one. The SEM images of Lucerne (alfalfa) and the commercial MCC showed that microcrystals of both MCC have similar morphology. They both represent an irregular, agglomerated, and elongated morphology. Overall, the properties of the prepared MCC are comparable to those of the commercial type, and can be used as food and pharmaceutical additives.