Utilization and Product Development-76



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Project Leader and Principal UC Investigators

Glenn Nader, livestock farm advisor, UC Cooperative Extension Butte/Sutter/Yuba Counties


Research to increase the demand for and use of California rice has focused on new rice products and improved cooking performance.

Rice marketing and utilization research has been under way at UCD since 1970. During 1974-76, a joint research effort was begun with the Western Regional Research Center (WRRC), USDA, Berkeley. The combined objectives concentrated on investigations to reduce stickiness of cooked California rice, on expanded uses of rice flour, and on the development, utilization, and stability aspects of other new rice products. The results are summarized below.

An instant rice was made from freeze-dried precooked Calrose frozen rice.

Freeze-dried rice is an excellent product which rehydrates readily in boiling water in a few minutes while retaining its color, flavor, and texture. It is easily prepared and results in rice as attractive and good as that freshly cooked. Aluminum-foil pouches protect against moisture and air and prevent deterioration from light and microorganisms.

New techniques have been developed for making frozen rice products.

While cooking and processing characteristics differ significantly between long-grain (southern), short-grain (pearl), and medium-grain (Calrose) varieties, results indicate that precooked Calrose rice can yield a convenience product which needs only to be heated before serving. The specially processed cooked rice was cooled, packaged in 12-oz boil-in-the-bag pouches or in 12-oz carton pouches, and then frozen at 0F. The frozen product, which is also fortified with niacin and thiamine, appears to be quite good in quality.

Studies were carried out on precooked instant rice to determine best methods of preparation.

Precooked medium-grain instant rice, dehydrated with hot air, was used in this study. Freezing the cooked rice before dehydration greatly facilitated the dehydration process, and eliminated lumping of the rice. Recommended packaging and storage methods have been developed from these experiments which should be useful to potential marketers of the new product.

An attractive fermented rice called "Lao-chao" was produced from a mixture of 2/3 Calrose and 1/3 sweet rice.

The fermented rice has a taste of sweet tartness, and a distinctive fruit aroma. Juice from the fermented product, containing 15% sugars and 2.6% alcohol, can be stored at 40F for 2 to 3 months without deterioration in quality. Fermented rice can be consumed as such, cooked with eggs, or used as a flavor booster for various fish and vegetable dishes.

Canned-rice experiments proved highly successful.

Studies were conducted to determine the quality of and processing required for canned Calrose rice fortified with kidney beans, garbanzo beans, and textured soy proteins. Calrose rice was the major component (more than 40%) in the formulation. The canned product contained more than 12% protein, compared with 6-7% in medium-grain rice alone. The many studies conducted in this project proved that a uniquely attractive canned rice ran be obtained when fortified with dry beans and soy proteins.

Rice-flour products have attracted considerable interest as a nutritious replacement for wheat. These products can be particularly useful to consumers allergic to wheat protein or on a low-sodium diet.

The development of a rice-flour bread formula has been the subject of national publicity by the press and trade journals. A commercial food manufacturer has also indicated plans to market the developed rice mix. The best breads incorporate short- and medium-grain rice flour. A goodquality vermicelli was also made from Calrose rice flour, and evaluations were made on the feasibility of substituting rice flour for wheat flour in making cookies.

Consumer studies indicate very little loyalty to brand or type in the purchase of cookies; thus, a new cookie could successfully challenge existing products if it met special dietary needs or could be demonstrated to have particular appeal. An overall evaluation of the many officially recognized tests comparing rice-flour with wheat-flour cookies made such a substitution look very promising.

Quick-cooking process has sparked commercial interest.

The USDA developed a dry quick-cooking method that uses a minimum number of steps. Using a centrifugal fluidized bed for the critical drying step, the new process is very flexible and applicable to all grains of white rice, and yields products similar to "minute rice." Brown rice and wild rice have also been processed satisfactorily.

The process utilizes a short 4-7-minute drying cycle with good control of texture and rehydration characteristics. Rotation of the dryer (300-400 RPM) produces a centrifugal force of about 10 times gravity, thus permitting an air drying velocity about 10 times that used in previously developed techniques. It is estimated that energy requirements, water usage, effluent water treatment, and disposal should be significantly reduced by the reductions in drying temperature, time, and precooking conditions. Three major food-processing companies have shown serious interest in commercializing this process, which yields a flavorful, nonpasty, quick-cooking product.

Consumer surveys in California confirm that rice grain length and ease and reliability of preparation are important considerations.

A rice-preference study was conducted in 1970-74. Regardless of preparation method, California consumers living in large metropolitan areas rated long-grain rice superior to the medium grain then available - in appearance, size, stickiness, and fluffiness. Recognition of these consumer preferences as to grain length, cooking ease, and reliability is basic to the future market potential.

Additional studies were conducted on family and children's consumption patterns. Children progress from baby foods to whatever the rest of the family eats. The quantity of rice consumed by families is equated to the frequency with which preferred rice dishes are served, rather than the variety of methods of preparation. Three percent of families interviewed used rice once a day; 18% indicated they served rice once a month; 38% served rice once a week or more. An even larger group, 42%, served rice more than once a month but less than once a week.

The focus of research on product and market development will sharpen in 1977 and beyond.

  1. Hot-air treatment of milled short or medium rice demonstrated a reduction of stickiness on subsequent cooking. Further experiments in 1977 will be designed to measure additional chemical characteristics of rices and the effects of pretreatment methods on stickiness.
  2. More work will be carried out on the precooking conditions of frozen rice, such as presoaking, boiling, and steaming treatments.
  3. Modified rice will be packaged and investigated for storage stability. Various parameters of time, temperature, and humidity, and their effects on color, consistency, peroxide value, sensory quality, etc., will be evaluated.
  4. Studies will be continued on the factors affecting the functional properties of rice flour made from medium-grain rice. Because rice is consumed mainly as whole grains, its full use in flour form remains inadequately explored. Some rice flours are produced from broken kernels and used in baby foods, mixes, sauces, and breakfast foods. Rice flour has already shown its potential as a raw material for prepared foods, especially for people allergic to wheat. The physical and chemical properties of rice flour may vary with varietal characteristics, method of milling, storage conditions, and packaging materials for protecting the product from moisture absorption. Very little is known about how these variables may affect the functional properties of rice flour, which may find new uses in pastry, cookies, crackers, snack foods, puddings, baby foods, and industrial applications.
  5. Work will be performed to study the chemical and physical characteristics of new rice varieties grown in California. These include M5 (medium-grain 5), S6 (short-grain 6), and the California-grown long-grain rice. Testing will include rehydration capability, protein level, minerals, cooking characteristics, and consistency of the product for rice processing. The chemical properties of the rice will be correlated with the functional properties.
  6. A program will be initiated to determine how best to stimulate the food industry to use these emerging study results. This should require about two years.


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