Production of Corn-Based Breakfast Cereal by Twin Screw Extruder

Abstract

The research on production of corn-based breakfast cereal by using Herman Berstorff laboratory Twin Screw Extruder ZE 25 x 33 D was carried out. The objectives were to find out the suitable quantity of soy flour fortified into corn formulate mixture to produce good texture, high nutritional value, low cost and good protein quality product. Breakfast cereal formula R'₂ 350 rpm, in which 16% defatted soy flour was fortified into 77% corn grit 5% sugar 1% CaCO₃ 1% mixed vitamins and 2% cocoa powder of total weight was obtained by feeding into extruder at 300 g/min feed rate, employing 350 rpm screw speed. The product was coated with chocolate flavoured for sensory evaluation. It gained the highest overall acceptability score 7.33 (9-Point Hedonic Scale) compared to NL.MLO, O.V.T.C and formula R'₅ 350 rpm when tested with out fresh milk and it’s score 6.95 when they were tested with fresh milk. It beared factory cost of 2.40 baht per 25 gms in OPP/Metallite PET with retail price of 5.00 baht or 200 baht per one kilogram or 170.65 baht per 100 gms of protein in the product. Nutritionally, the formula R'₂ 350 rpm contained per 100 gms, 11.72 g or 3.16 g of protein per 100 kg-cal., 1.86 g fat, 4.0 g ash, 1747.8 I. U vitamin A, 0.48 mg vitamin B₁, 0.43 mg vitamin B₂, 0.37 mg vitamin B₆, 2.98 mg niacin, 723.8 mg calcium, and 3.03 mg iron, 119.7g/l apparent density and 3.42 expansion ratio when compared to 9 samples of commercial breakfast cereal which costed 233.30-390.90 baht per one kilogram or 300.50-698.00 baht per 100 gms of protein in product which 4.7-9.2 g or 1.07-2.43 g of protein per 100 kg-cal. The breakfast cereal formula R'₂ 350 rpm was the cheapest in retail price and the highest in nutritional value. Beside it’s protein content (3.16) is above the standard limit regular human food which should contain at least 2.5-3.0 grams of reference protein per 100 kg-cal. The protein quality of the breakfast cereal also showed higher chemical score of lysine , 73 and methionine + cystine, 117 compared to 31 and 165 of corn grit. And the corn-based breakfast cereal contained a very good source of essential amino acids ( >80% of FAO pattern ) except lysine. Thus it can conclude that the corn-based breakfast cereal from this research is high nutritive value, low cost and good for consumption.