Effects of Different Grinding Methods on Morphological, Textural Properties and Pasting Profiles of Mr220 Rice Flour

Abstract

Three different grinding techniques (dry, semi-wet, and wet) were employed in rice flour production. Investigation on the effects of the grinding techniques on starch damage percentage, particle size distribution, pasting profiles, morphological and textural properties of rice flours produced were evaluated. Wet grinding resulted in significantly (p< 0.05) has lower percentage of damaged starch (3.24 %) than other grinding methods. Morphological studies (microscopy and particle size analysis) have reflected significant differences among rice flours granule shapes. The granules displaying different shapes of polygonal, round and angular forms, with some as an individual granule while others tend to attached together. Wet grinding technique also yielded flour that exhibit significantly (p< 0.05) with higher gel hardness (16.62 g). Pasting profiles showed that pasting temperature for rice flour produce using these three grinding methods varied between 80.15 -80.42 °C. Results revealed that the three grinding techniques clearly affected the physicochemical properties of rice flour. The results from this study play an important role in the selection criteria of rice flour with desirable pasting and textural properties for manufacturing rice-based product.Keywords: Grinding techniques, particle size, pasting profiles, rice flour, starch damage Abstrak Tiga jenis teknik pengisaran (kering, separa basah, dan basah) telah digunakan dalam penghasilan tepung beras. Kajian ke atas kesan teknik pengisaran pada peratusan kerosakan kanji, taburan saiz partikel, profil pempesan, sifat morfologi dan tekstur tepung beras yang dihasilkan telah dianalisa. Pengisaran basah menyebabkan peratusan kanji rosak (p< 0.05) lebih rendah secara signifikan (3.24 %) berbanding kaedah -kaedah pengisaran lain. Kajian morfologi (mikroskopi dan analisis saiz zarah) telah menunjukkan perbezaan yang signifikan antara tepung beras dari segi saiz dan bentuk granul yang terhasil. Granul memaparkan bentuk berlainan seperti poligon, bulat dan bentuk bersudut, samada wujud sebagai granul sendirian ataupun berkluster. Teknik pengisaran basah juga menghasilkan perbezaan yang signifikan (p< 0.05) berbanding teknik pengisaran lain dari segi kekerasan gel yang lebih tinggi (16.62 g). Profil pempesan menunjukkan suhu pempesan untuk tepung beras yang dihasilkan menggunakan ketiga -tiga kaedah pengisaran berada dalam julat antara 80.15 -80.42 °C. Hasil kajian dengan jelas menunjukkan bahawa tiga teknik pengisaran memberi kesan kepada ciri -ciri fizikokimia tepung beras. Hasil kajian ini sangat penting dalam menentukan kriteria tepung beras berdasarkan sifat dan sifat tekstur yang dikehendaki untuk pembuatan produk berasaskan beras.Kata kunci: Teknik pengisaran, saiz partikel, profil pempesan, tepung beras, kerosakan kanji

Efficient processing of cassava starch: physicochemical characterization at different processing parameters

“…According to Table 5, the larger the milling size of cassava starch, the higher its gel strength. This is because dry grinding caused the breakdown of the starch polymer chains and reduced the retrogradation ability of starch and finally reduced its gel strength (Ahmad et al, 2016). Thus, cassava starch with the largest milling size (63 µm) will be suitable as food binder and texture enhancer in food.…”