Studies On The Preservation Of Wet Raw Noodles

Wet raw noodles, as a kind of health food, is increasingly getting into popular recently owing to its properties of fresh, good taste And sweet-scented. Since the moisture content of wet raw noodles is high, the wet raw noodles were apt to deteriorate at room temperature, especially in summer when the air temperature is high. The trait of quality change and the corresponding fresh-keeping methods of wet raw noodles were researched in this paper in order to prolong its shelf life.The storage experiment indicated that microorganism was a most important factor which resulted in the deterioration of wet raw noodles .The microorganism promptly propagated in the wet raw noodles in the process of storage, as a result, the water absorbing capacity, as a kind of stewing trait, was decreased obviously. The hardness, maximum shearing force and snap force were as three major parameters of quality evaluation were deceased obviously as well. The color of wet raw noodles became yellow along with the prolonging of storing time. However, the loss rate of dry matter was not significant. The amount of microorganism of the wet raw noodles without any fresh-keeping treatment went beyond the national standard and could not be eaten, and the color of Wet raw noodles changed to yellow from white after the noodles were stored 12 hours.The quality properties of wet raw noodles were evaluated by Texture Profile Analysis connecting with organoleptic investigation in this paper. The result showed that the water absorption and the hardness, maximum shearing force, snap force could reflect the process of the qualitative change of wet raw noodles. When the water absorption was more than 135% , the hardness ranged from 3500g to 4000g,the maximum shearing force ranged from 700g to 1000g, and the maximum snap force ranged from 25g to 35g, the wet raw noodles presented good taste and the grade of its quality was high by organoleptic investigation.The sterilizing effect of chlorine dioxide and hydrogen peroxide respectively increased with increasing dosage. The sterilizing rate was about 98%, either the additive amount of chlorine dioxide was 0.05mg/g or the additive amount of hydrogen peroxide was 0.5mg/g. The strong oxidation of chlorine dioxide and hydrogen peroxide had the better whitening effect. Wet raw noodles bleached evidently adding either 0.03mg/g chlorine dioxide or 0.2mg/g hydrogen peroxide. The texture of noodle was affected by both chlorine dioxide and hydrogen peroxide. Water absorption and tensile strength were both decreased with increasing additive amount of chlorine dioxide and hydrogen peroxide, but the hardness and maximum shear force were reverse. The higher the amount of chlorine dioxide and hydrogen peroxide were added, the greater the effect of these parameter were changed, and the worse taste of noodle were become. Water absorption and texture parameter were beyond the variable range keeping the better taste, and the texture of noodle decreased badly, when adding 0.05mg/g chlorine dioxide and 0.4mg/g hydrogen peroxide, respectively. The storage experiment indicated stability of wet raw noodle of adding hydrogen peroxide was not as good as the stability of wet raw noodle of adding chlorine dioxide in alkali condition. Though the sterilizing rate could reach as high as 99% by sterilizing the flour which was used to produce wet raw noodles by microwave for 60 seconds, the water absorption of wet raw noodles was much less than 135%, which was beyond the variable range and deceased the quality of the noodles severely. At the same time, the color of flour changed a lot after handling the flour 60 seconds by microwave, the aberrationâ–³Eab was higher than 9.0, the color of flour became yellow obviously which deceased the apparent quality of the noodles and it also produced burned taste.Cooperating chlorine dioxide with microwave(first step: treated the flour 50 seconds by microwave, second step: added 0.03mg/g chlorine dioxide in water), the sterilizing rate exceeded 99%, the storage time was longer, and the texture of noodle was kept as good as adding either 0.03mg/g chlorine dioxide or microwave sterilize 50s. The storage experiment indicated that the amount of microbe of the noodle was not beyond national sanitation standard after storing 20d, water absorption was also kept at about 137%, the hardness was at about 3600g, the maximum shear force was between 800g and 850g, the tensile strength was at about 23g, all the parameters were kept at the variable range, but the color of the noodle was yellow, color differenceâ–³Eab was 3.5.