Improved microbial quality of buckwheat using antimicrobial solutions in a fluidized bed.

Buckwheat (Fagopyrum esculentum, Moench) is a specialty crop of interest because of its numerous nutritional, health, and agronomic benefits. A high microbial load on the seed often limits its export and use in functional foods; therefore, these generally recognized as safe antimicrobial treatments were evaluated for buckwheat disinfection: ozone gas, ozonated water, acetic acid (AA), acidic calcium sulfate (ACS), and combinations thereof. The liquid treatments were sprayed on buckwheat grain in a fluidized bed and the treated buckwheat was analyzed for aerobic plate count (APC) and yeast and mold count (YMC). Ozone gas and ozonated water treatments were not significantly (P < 0.05) effective in reducing the microbial load, and AA + ozonated water had significant but low effectiveness. Electron microscopic imaging suggested that rough surfaces and crevices in the seed hull shielded microbes from ozone treatments. Effectiveness of treatments was also limited by the industry limits on the amount of moisture that can be added to buckwheat grain. The ACS (50 mL/L) treatment was most effective with 3.9-log10 reduction in APC and complete elimination of YMC. ACS (50 mL/L) caused bleaching and increased redness. Sufficient reduction of microbes could be achieved at a lower concentration of ACS, thereby reducing the effect on color.

[The role of gene tepal-like bract (TLB) in the separation between the bracts and perianth in Fagopyrum esculentum moench].

The morphological and genetic studies of the tlb mutant of common buckwheat Fagopyrum esculentum from the collection of the All-Russia Research Institute of Legumes and Groat Crops have demonstrated that gene TLB controls an important stage of flower development-it determines the lower boundary of simple perianths. The loss of TLB gene function leads to changes in the structure of the bract from scale-like to tepal-like. Gene TLB is assumed to limit, on the basal side, the region of the expression of genes determining the development of flower organs as petals.

[The ultracytochemical localization of ATPase activity in pollen tube and stigma of Fagopyrum esculentum after compatible and incompatible pollination].

Ultracytochemical localization of adenosine triphosphatase (ATPase) activity in stigmas, pollens and pollen tubes of Fagopyrum esculentum was performed with the cytochemical method of lead phosphate precipitation. The results were as follows: (1) Lower activities of ATPase appeared in stigma cells at 0.5 hour after compatible and incompatible pollination. Stigma surface and pollen grains attached on stigma showed higher ATPase activities after compatible pollination and lower or no activities after incompatible pollination at 0.5 hour. ATPase localized on endoplasmic reticula and sperm cell in pollen grain. (2) Lower ATPase activities appeared both in stigma cells and pollen tubes in style at 1.5 hours after incompatible pollination. Pollen tube stopped growing and the degeneration of its cytoplasma began; on the contrary, at 1.5 hours after compatible pollination, higher ATPase activities were detected both in stigma cells and pollen tube in style. ATPase localized mainly on plasmolemma, in cytoplasmic matrix of stigma cells and in mitochondria, dictyosome, plastid envelop, and on the wall of pollen tube as well. The present study indicated that the stop of pollen tube growth after self-incompatibility of Fagopyrum esculentum resulted not only from the nutrient starvation of pollen tube, but also from its metabolic disorder in incompatible style.

[The ultrastructures of storage protein accumulation in aleurone layer and cotyledons of Fagopyrum esculentum].

The ultrastructures of storage protein accumulation in cotyledons and aleurone layer in buckwheat (Fagopyrum esculentum Monch) were investigated by electron microscopy. (1) On 15 days after anthesis (DAA), there are many dictyosomes and vacuoles accumulating protein in cytoplasm of the outer layer endosperm cells. These cells containing abundant aleurone grains (1-2 microm in diameter) from vacuoles accumulated storage protein form aleurone layer where division of aleurone grain is also observed on 25 DAA. (2) On 20 DAA, protein begins to accumulate in vacuoles of cotyledon cells. At the early stage of protein deposition, vacuoles are becoming smaller ones by ingrowth of tonoplast or by pinch-off. A multitude of ribosomes, many dictyosomes and electron-dense vesicles (0.1-0.7 microm in diameter) coated with membrane are observed in cytoplasm of cotyledon cells at every stage of protein accumulation. Originated from the separation of saccules containing protein at the fringe of dictyosome, these vesicles (0.1-0.2 microm in diameter) probably increase their volume by fusion each other. They play the leading role in transporting storage protein into vacuoles that become PSVs in cotyledon cells of buckwheat. On 25 DAA, there are many PSVs (1-3 microm in diameter) and some vesicles (0.1-0.7 microm) filled with protein in mature cotyledon cells. These vesicles may be also play a part in accumulating storage protein in mature buckwheat seed.