NON-TRADITIONAL PRODUCTS FROM CORN

Crop Production/Industries,

Physicochemical properties and leaching behavior of eight U.S. long-grain rice cultivars as related to rice texture

There are many long-grain rice cultivars produced commercially in the U.S.; however, little work has been done on correlating the structure and physicochemical properties of starch with their texture. The physicochemical properties, leaching behavior, and texture attributes of eight longgrain rice cultivars were studied. Differences were observed in the approximate composition of kernels, including crude protein (6.6-9.3%), crude lipid (0.18-0.51%), and apparent amylose content (25.5-30.9%). These cultivars also differed slightly in thermal properties, such as onset temperature (73.7° to 77.4°C) and peak temperature (78.8° to 81.9°C). Although they showed a similar pasting temperature, their peak viscosities ranged from 680 to 982 Brabender units. The amount and the molecular size distribution of the leached starch molecules varied greatly among the samples. The leached amylose, instead of the apparent amylose, was suggested to play an important role in cooked rice texture

Factors affecting sorghum protein digestibility

In the semi-arid tropics worldwide, sorghum (Sorghum bicolor (L.) Moench) is cultivated by farmers on a subsistence level and consumed as food by humans. A nutritional limitation to its use is the poor digestibility of sorghum protein when wet cooked. The factors affecting wet cooked sorghum protein digestibility may be categorised into two main groups: exogenous factors (grain organisational structure, polyphenols, phytic acid, starch and non-starch polysaccharides) and endogenous factors (disulphide and non-disulphide crosslinking, kafirin hydrophobicity and changes in protein secondary structure). All these factors have been shown to influence sorghum protein digestibility. More than one factor may be at play at any time depending on the nature or the state in which the sorghum grain is; that is whether whole grain, endosperm, protein body preparation, high-tannin or condensed-tannin-free. It is proposed that protein crosslinking may be the greatest factor that influences sorghum protein digestibility. This may be between ?- and ß-kafirin proteins at the protein body periphery, which may impede digestion of the centrally located major storage protein, a-kafirin, or between ?- or ß-kafirin and a-kafiri

High-value cassava: From a dream to a concrete reality

Cassava (Manihot esculenta Crantz) is an important food security crop for many tropical and subtropical countries. It is also acquiring an increasing role in rural development as raw material for different industries. The most important industrial uses of cassava are as a source of energy in the feed industry, the bio-ethanol and starch industries, and for processed food. For cassava to be a suitable raw material for different industrial pathways, it has to have a competitive price, which is dependent on high and stable fresh root production, high dry matter content and adequate cultural practices that will maximize yields and reduce production costs. For years many institutions have successfully satisfied these needs. However, to consolidate and expand the industrial uses of cassava, the cassava breeding project at CIAT began increasing the emphasis in the search for value-added traits with the turn of the millennium. Several strategies have been implemented simultaneously. For the feed industry, the main objective is enhanced nutritional quality, particularly with regard to protein and pro-vitamin A carotenoids content. For the starch industry, amylose-free and high-amylose mutations have been identified. Inbreeding has been introduced to cassava genetic improvement because it offers many advantages, including a facilitated identification of useful recessive traits including new plant architecture types. Ongoing research for the production of doubled-haploid lines will reduce the time required to reach full homozygosity. Finally, CIAT has set up a high capacity root-quality laboratory to routinely screen the roots of the thousands of new genotypes generated every year. (Résumé d'auteur

A novel superior factor widely controlling the rice grain quality

Synthesis of storage starch and protein accumulation is the main action of endosperm organogenesis in term of the economic importance of rice. This event is strongly disturbed by abiotic stresses such as high temperature; thus, the upcoming global warming will cause a crisis with a great impact on food production^1,2^. The enzymes for the protein storage and starch synthesis pathway should work in concert to carry out the organogenesis of rice endosperm^3-5^, but the regulatory mechanism is largely unknown. Here we show that a novel regulatory factor, named OsCEO1, acts as the conductor of endosperm organogenesis during the rice grain filling stage. The physiological properties of _floury-endosperm-2_ (_flo2_) mutants showed many similarities to symptoms of grains developed under high-temperature conditions, suggesting important roles of the responsible gene in sensitivity to high-temperature stress. Our map-based cloning identified the responsible gene for the _flo2_ mutant, _OsCEO1_, which has no homology to any genes of known function. The _OsCEO1_ belongs to a novel conserved gene family and encodes a protein composed of 1,720 amino acid residues containing a TPR (tetratricopeptide repeat) motif, which is considered to mediate a protein-protein interaction. The yeast two-hybrid analysis raised an unknown protein showing homology to a late embryogenesis abundant protein and a putative basic helix-loop-helix protein as candidates for the direct interactor for _OsCEO1_, whereas no enzyme genes for the synthesis of storage substances were detected. The _flo2_ mutant exhibited reduced expression of several genes for putative regulatory proteins as well as many enzymes involved in storage starch and proteins. These results suggest that _OsCEO1_ is a superior conductor of the novel regulatory cascade of endosperm organogenesis and may have important roles in the response to high-temperature stress

Structure and Function of Starch and Resistant Starch from Corn with Different Doses of Mutant Amylose-Extender and Floury-1 Alleles

Four corn types with different doses of mutant amylose-extender (ae) and floury-1 (fl1) alleles, in the endosperm, including no. 1, aeaeae; no. 2, fl1fl1fl1; no. 3, aeaefl1; and no. 4,fl1fl1ae, were developed for use in making Hispanic food products with high resistant starch (RS) content. The RS percentages in the native starch (NS) of 1−4 were 55.2, 1.1, 5.7, and 1.1%, respectively. All NS were evaluated for pasting properties with a rapid viscoanalyzer (RVA) and for thermal properties with a differential scanning calorimeter (DSC). NS 1 had a low peak viscosity (PV) caused by incomplete gelatinization, whereas NS 3 had the greatest PV and breakdown of all four starch types. On the DSC, NS 2 had the lowest onset temperature and greatest enthalpy. NS 1 and 3 had similar onset and peak temperatures, both higher than those of NS 2 and 4. The gel strength of NS heated with a RVA was evaluated by using a texture analyzer immediately after RVA heating (fresh, RVA-F) and after the gel had been stored at 4 °C for 10 days (retrograded, RVA-R). NS 1 gel was watery and had the lowest strength (30 g) among starch gel types. NS 3 gel, although exhibiting syneresis, had greater gel strength than NS 2 and 4. The structures of the NS, the RS isolated from the NS (RS-NS), the RS isolated from RVA-F (RS-RVA-F), and the RS isolated from RVA-R (RS-RVA-R) were evaluated by using size exclusion chromatography. NS 1 had a greater percentage of amylose (AM) (58.3%) than the other NS (20.4−26.8%). The RS from all NS types (RS-NS) had a lower percentage of amylopectin (AP) and a greater percentage of low molecular weight (MW) AM than was present in the original NS materials. The RS-RVA-R from all starches had no AP or high MW AM. The percentages of longer chain lengths (DP 35−60) of NS were greater in 1 and 3 than in 2 and 4, and the percentages of smaller chain lengths (DP 10−20) were greater in 2 and 4 than in 1 and 3. In general, NS 3 seemed to have inherited some pasting, thermal, and structural characteristics from both NS 1 and 2, but was distinctly different from 4

REVIEW: Current Status of Extenders and Cryoprotectants on Fish Spermatozoa Cryopreservation

An important component of many studies of cryopreservation of fish spermatozoa is the type of extenders and cryoprotectants. The suitability of extenders and cryoprotectants differs from one fish to another. There are many studies have been done in cryopreservation of fish spermatozoa. However, there are few review have been done. This review reveals some aspects of cryopreservation especially the role of extender and cryoprotectant in fish sperm cryopreservation. Fish produce high viscosity of sperm and in some cases only small volume is produced. Before cryopreserved in liquid nitrogen, sperm have to dilute with extenders and for long-term cryopreservation, cryoprotectants are needed to protect the sperm cell from cold and hot shock treatments and prevent cell dehydration during pre-freezing, freezing and post thawed. The suitability of extenders and cryoprotectants differs from one fish to another. Over the last decade, studies on the cryopreservation of mammalian sperm, animal husbandry sperm and human sperm have progressed significantly but studies on fish sperm is still confined to some aquatic

Development and identification of cassava clones with special starch characteristics

Cassava (Manihot esculenta Crantz) is an important food security crop for many tropical and subtropical countries. It is also acquiring an increasing role in rural development as raw material for different industries. The most important industrial uses of cassava are as a source of energy in the feed industry and for the starch and ethanol industries. To consolidate and expand the industrial uses of cassava, an increased emphasis in the search for value-added traits, while maintaining or enhancing its productivity, has recently been given by the cassava-breeding project at CIAT. Different strategies have been implemented simultaneously. Since most traits offering qualitative changes in starch properties are recessive in nature, these strategies rely heavily in the self-pollination of a wide range of cassava genotypes to expose useful recessive traits. Ongoing research for the production of doubled-haploid lines will reduce the time required to reach full homozygosity. Plants from irradiated seed in a mutation-breeding project have been evaluated in the field and many self-pollinations have been made to implement the TILLING system. Several novel starch types have been identified. A waxy starch mutation has been fully characterized. In addition, several other mutations have been identified and are currently being characterized. Among them a small-granule type which showed (in a preliminary evaluation) higher-than-normal levels of amylose. Another abnormal starch with granules that looked hollow through optical microscopy was also identified. There were several other abnormal types that need further analyses because the preliminary evaluations were made on single plants derived from botanical seed. All these off-types have been cloned and will be harvested again by the end of 2007. (Résumé d'auteur