Effective compounds for the isolation of starch in green banana were searched. As a result, it was clarified that the starch in green banana can be easily isolated with a dilute alkaline solution. For example, 2 parts of 0.2 N NaOH solution were added to one part of sliced green banana in a mixer and homogenized. The homogenate was sieved with a 60-mesh screen to eliminate coarse fibrous tissues and left overnight. Then solid matters other than the starch were coagulated and floated up, and the starch was firmly precipitated. By this method pure starch corresponding to 10 percent of green banana was obtained.

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Some properties of banana starch isolated with a dilute alkaline solution from green banana were compared with those of corn starch, sweet potato starch and potato starch. It was found that the banana starch has extremely characteristic properties and the position of it on the "Starch scale" varies considerably with the respective measuring items . That is to say, the shape of banana starch granules is characteristic of thin flat discs, from which it seems that high fluidity of banana starch results . Moreover, banana starch show a worse digestibility by amylase action in spite of its easier dissolution in DMSO . Beside these, the content of amylose is the lowest among the four sorts of starch. The patterns of gelatinization resemble those of sweet potato starch.

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At the achroic point of hydrolysis of amylose by the partially purified a-amylase from dried barley malt for brewing, the digest comprised ca. 18 wt.% of maltohexaose, ca. 35 wt.% of maltoheptaose and ca. 15 wt.% of maltooctaose. Maltoheptaose was main product. The maltooli gosaccharides produced were separated by gel filtrations on Sephadex G-15, and successively on Bio-Gel P-2.

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Bacon's method was modified for the large scale preparation of alkyl β-fructofuranosides. A mixture containing invertase, sucrose and alkyl alcohol was incubated at 20°C for 2 hr. The reaction product was chromatographed on carbon-celite column with deionized water and 1.5% ethanol. The eluate which contained mainly alkyl β-fructofuranoside was purified by ion exchange chromatography on Dowex-1, borate form . Under these conditions, purified alkyl β-fructof uranoside, the yield of which ranged from 600 to 800 mg, was able to obtain three working days. The product was homogenous in thin layer chromatography on cellulose . Thin layer chroma tography of the acid hydrolysates of the methyl and ethyl β-fructofuranosides revealed the presence of fructose which was only sugar component. Nuclear magnetic resonance analysis of the preparations indicated the presence of methoxyl and ethoxyl group respectively. [a]D Values of methyl and ethylβ-fructofuranosides. prepared were -48. 6, c= 1.5 and -39. 3, c=2 respectively.

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