Study On Preparation And Application Of Modified Waxy Rice Starch Used In Salad-dressing Without Eggs

In recent years, the traditional salad dressing used the egg, but it is more and more obvious that the cholesterol of egg yolk is a threat to people's health in the traditional salad dressing. And there were many events that were related to salmonella infected as the eggs used in salad dressing were not cleaned up. And freshness of eggs could also affect the propeties of salad dressing, so more and more no-eggs-salad dressing came to the market. The salad dressing flour has mushroomed like bamboo shoots after a spring rain. In this flour, modified starches are the main ingredients.Firstly, hydroxypropyl waxy rice starch was prepared followed other learners'method. And then hydroxypropylated starch was used as raw meterials, sodium trimetaphosphate as reagent to prepare cross-linked hydroxypropylated starch. The optimized condition: the starch slurry 40%(w/w), sodium trimetaphosphate 0.03%(w/w), reaction time 3h, pH 10, reaction temperature 40℃. the result:phosphorus content about 0.025%.The waxy rice starch was used as raw material to get octenyl succinate esterification optimum conditions:reaction temperature 35℃, starch slurry 35%(w/v), pH 8.5, reaction time 6h. The test showed that the degree of substitution reached 0.0179.Secondly, compared to the raw starch, the gelatinization temperature of hydroxypropyl waxy rice starch deareased, viscosity increased, but acid-resistant, salt-resistant and the shear resistance were not significantly improved. After cross-linking, there was a definite increase in acid-resistant, salt-resistant and the shear resistance. And the effects increased with the addition of degree of crosslinking. Some research on OSA starch pastes were also studied. Results showed that as the substitution degree increased, gelatinization temperature decreased, viscosity increased, emulsifying properties and the stability of emulsion increased, but the acid-resistant, salt-resistant, shear-resistant properties dropped sharply. After compunding of the two modified starches as 1:1(w/w),the paste propeties was improved; and when the starch slurry concentration was 2%, the emulsifying arrived 94.4% and the emulsion stability was 94.1%.Finally, mixture of the pre-gelatinized waxy rice starches was studied, we got the best combination formula(contained 50%-60% oil):pregelatinized cross-linked hydroxypropylated waxy rice starch(A) 16g, pregelatinized OSA waxy rice starch(B) 14g, water 150g, white vinegar 20g, sugar 30g, salt 9g, oil 350g. Namely, A 2.7%, B 2.4%, water 25.5%, white vinegar 3.4 %, sugar 5.1%, salt 1.5%, oil 59.4%. By comparing to the commercial products (BERRY), our product had a similar rheology propety.After sensory evaluation, the self-made salad dressing is milky white, stable, and the product had a good taste.