Rice Utilization & Product
Development-75
 
 

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Project Leader and Principal UC Investigators

B.S. Luh

John Williams

Ann Pryzyla

Linda Leethem

 

Highlights

Expansion of rice utilization research needed and planned. UCD scientist makes progress in developing processes for:

  1. Fermented rice products
  2. Rice flour products
  3. Precooked frozen rice
  4. Precooked instant rice.

USDA scientists developing new processes to expand market demand for California rice, but need more support funds.

Although world rice stocks were dangerously low in 1973 and 1974, most world rice markets now seem temporarily glutted and upset by the bumper worldwide rice crop in 1975. Orderly marketing of California's record 1975 rice crop of 1,504,000 tons will be a challenge. Even so, the long-term worldwide rice outlook remains good, most marketing economists agree. The earth's population continues to increase rapidly, especially in the rice-consuming areas. For economic stability, however, we must work vigorously to increase our share of the domestic market. That is why research for several years has placed emphasis on developing products made from California rice. Rice products attractive to consumers should stimulate and broaden the domestic demand for California rice.

The project began with a 2-year study at UCD of consumer product preferences and knowledge of rice characteristics (1971-1972). Since 1973, scientists in the Department of Food Science and Technology, UCD, have conducted research on the processing characteristics and possibilities of California rice varieties.

SUMMARY OF CURRENT YEAR'S RESULTS:

1) Calrose can be fermented with a starter in the presence of 1/3 its weight of sweet rice to produce an appealing ready-to-eat product which is very attractive in aroma, flavor, and texture. The product can also be used in cooking other foods to make more tasty dishes.

þ 2) Flour made from Calrose rice has a good potential for use in commercial and home bakery products.

þ 3) Various factors affecting the texture of precooked frozen Calrose rice were investigated. Hydrogenated vegetable oil added at 5% to the cooking water (with 0.5% Tween 60 as emulsifer) can help keep cooked rice grains from sticking together. Careful control of the ratio of cooking water to soaked rice between 1.25/1.00 and 1.10/1.00 can yield a cooked rice of excellent texture and flavor acceptance. Salt of 1.0% by weight added to the cooking water also improves flavor acceptance of the frozen rice. The texture of cooked rice is related to the crystallization of rice starch by retrogradation.

4) Precooked Instant Rice.

Freezing cooked rice before dehydrating it in a hot-air tunnel greatly facilitates dehydration--and in addition, the rice kernels will not stick together in lumps when dehydrated.

USDA WESTERN REGIONAL RESEARCH LABORATORY (Berkeley, California) scientists have conducted research on the utilization of California rice varieties. Although that research was not funded by the Rice Board, liaison has been maintained with that Laboratory by your Board and by UCD researchers to ensure coordination with our research utilization research. Like us, that organization has had only limited funds for rice utilization research.

Using California rices and available limited funds, USDA scientists have studied:

þ 1) Reduced stickiness. Hot-air treatment of the surface of short- or mediumgrain milled rice reduces stickiness. Parameters of time and temperature of treatment, rice variety, and cooking procedures have been evaluated. Further improvements appear possible (e.g., by coating rice grains with oil before hotair treatment). Chemical modification of the grain surface and its effect on stickiness need investigation.

2) Quick-cooking rice. A centrifugal fluidized bed dryer has been used to prepare quick-cooking short- and medium-grain white rice. Pretreatment steps before drying (including cooking, soaking, and quenching) have been thoroughly studied. The new process reduces effluent and energy requirements, and greatly simplifies quick-cooking California rice preparations. Some further work is needed to optimize different steps in the process, but the main need is studies on utilization of this quick-cooking rice in various consumer products. Consumer acceptance should be tested.

þ 3) Rice bread. Yeast-leavened breads have been prepared from rice flour. Evaluation of many gums showed that only certain hydroxypropyl methylcelluloses were useful additives capable of substituting for wheat gluten properties. Further improvements in grain texture and appearance appear feasible, and further investigations are needed of shelf-life stability and improved formulation mixes for home use.

4) Rice polish. Despite progress, a need remains to: a) fully research the technology of preparation and incorporation into products of rice polish; and b) expedite governmental action to include this highly nutritious rice fraction into nutritionally rich, low-cost, cereal-based foods. This presents a new program, but a ready market potential is obvious.

 

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