James R. Daniel

Structure of chia seed polysaccharide exudate

Abstract Chia seed gum varies in molecular weight from 0·8 to 2·0 × 106 daltons, as determined by gel filtration. β- d -Xylose, α- d -glucose, and 4-O- methyl -α- d -glucuronic acid were obtained on hydrolysis in the respective ratios of 2:1:1. An aldobiouronic acid, 2-O-(4-O- methyl -α- d -glucopyranosiduronic acid)- d -xylose , was obtained by partial hydrolysis. A tentative structural unit proposed for the polysaccharide is a tetrasaccharide with 4-O- methyl -α- d -glucoronopyranosyl residues occurring as branches at O-2 of some β- d -xylopyranosyl residues in the main chain consisting of (1→4)-β- d -xylopyranosyl-(1→4)-α- d -glucopyranosyl-(1→4)-β- d -xylopyranosyl units. A linear tetrasaccharide was characterized that incorporates these structural features.

MOLECULAR STRUCTURE OF STARCH

Publisher Summary Starch is a homoglycan composed of a single type of sugar unit, regardless of the source of the starch. Starch was established as a polymer by the small freezing point depression observed for its aqueous solution. The hydrolytic investigations of starch were taken as proof of its poly(D-glucosyl), or D-glucan, nature. However, obtaining a quantitative yield of D-glucose from a pure glucan is difficult. The identity and structure of isomaltose is of considerable importance in ascertaining the structure of amylopectin. A procedure for separating starch fractions involves the complete dispersion of starch granules in a hot aqueous medium and treatment with 1-butanol to allow, on cooling, the formation of large crystalline rosettes of amylose-1-butanol complex. These could be separated by centrifugation or filtration. Pure amylose is obtained on re-disolution and re-precipitation as the 1-butanol complex with the final removal of 1-butanol by distillation from a hot suspension.

Beverage vs. solid fruits and vegetables: effects on energy intake and body weight.

Beverage consumption has been implicated in weight gain, but questions remain about the veracity of the association, whether the relationship is causal and what property of beverages is responsible. It was hypothesized that food form is the most salient attribute. Thus, a randomized controlled trial of food form was conducted. Energy‐matched beverage or solid forms of fruits and vegetables were provided to 34, lean or overweight/obese adults for two 8‐week periods with a 3‐week washout interspersed. Dietary compensation was incomplete (beverage 53% solid 78%) and body weight increased after the beverage (1.95 ± 0.33 kg) (77% fat mass) and solid (1.36 ± 0.30 kg) (85% fat mass) treatments (both P < 0.0005). Differences between food forms were not significant. The lean group had the highest dietary compensation (119%) and no significant weight change (0.84 ± 0.53 kg) after consuming the solid fruits and vegetables whereas the overweight/obese group had lower compensation and significant weight gain during the solid arm (46%, 1.77 ± 0.32 kg, P < 0.0001). In contrast, incomplete dietary compensation and weight gain occurred in both the lean (43%, 1.61 ± 0.44 kg, P = 0.003) and overweight/obese (61%, 2.22 ± 0.47 kg, P < 0.0005) groups during the beverage arm. Secondary analyses revealed the obese group gained more weight than the lean and overweight groups during the beverage intervention (P = 0.024). These data demonstrate energy consumed as beverages may be especially problematic for weight gain. They also indicate that advice to increase fruit and vegetable consumption should emphasize total energy intake because the additional energy contributed may promote weight gain, especially among overweight and obese individuals.

Isolation of Small Starch Granules and Determination of Their Fat Mimic Characteristics

ABSTRACT Small starch granules from wheat and amaranth were isolated and examined by light microscopy (wheat), scanning electron microscopy (wheat and amaranth), and rapid viscosity (RVA) analysis. The isolated wheat and amaranth starches were incorporated into reduced-fat frozen dessert mixes (2%, w/w) and the frozen desserts were characterized by sensory analysis for smoothness, creaminess, and preference. The results of the sensory analysis suggest that up to 50% of the fat in a frozen dessert may be replaced when substituted by these starches at the 2% level (w/w).

Surface Derivatization of Corn Starch Granules

ABSTRACT Commercial corn starch, treated with stearoyl chloride in carbon tetrachloride and triethylamine, is surface-derivatized without noticeable swelling. Granules that are reacted with chloroacetic acid under similar conditions undergo surface etherification, visibly identified by their color binding with fuchsin. Interestingly, the dye experiment indicates surface-derivatization as well as derivatization of the granule central interior, suggesting reagent penetration to the granule interior through pores and derivatization of a lower density porous center. Esterification of corn starch granules treated with glucoamylase have five times greater esterification than normal corn starch granules. Placed in water, these and palmitoylated granules have a fatty feel to the fingers. Stearoylated corn and amaranth starches showed indications for use as fat replacers in frozen desserts.

Synthesis of 3-C-(hydroxymethyl)erythritol and 3-C-methylerythritol

3-C-(Hydroxymethyl)erythritol was prepared from 3-C-(hydroxymethyl)-2,3-O-isopropylidene-D-erythro-tetrofuranose (4) by hydrolysis followed by reduction, or by reduction followed by hydrolysis. Monotosylation of 4, followed by reduction with lithium aluminum hydride and hydrolysis, afforded 3-C-methylerythritol.

Principal Changes in Starches during Food Processing

Starch, the main supplier of dietary calories to the world’s human population, has many chemical and physical characteristics that set it apart from all other food components and even all other carbohydrates. It is important that food processors take note of the structural and behavioral characteristics of starch and develop an understanding of its unique properties so as to avoid food processing difficulties and to take advantage of its numerous beneficial qualities. The chemistry and technology of starch has been reviewed recently in great detail (Whistler et al 1984).

CARBOHYDRATES CONTAINING SULFUR

Abstract Thioglycosides with sulfur as the glycosidic bridge are naturally occurring. They have been examined chemically and also biochemically wherein they aid in establishment of enzyme activity. Sugars and sugar nucleoside derivatives with sulfur—and sometimes selenium and nitrogen—replacing the ring oxygen show interesting chemistry and are of great potential usefulness in medicine as indicated by initial biochemical investigations. Their value in biochemistry as analogs of natural structures is proving of useful interest. Carbohydrates with sulfur at positions other than at the anomeric carbon or with ring involvement have interesting chemical properties. This review presents a general survey of carbohydrates containing sulfur, of their special methods of synthesis, their special chemical properties and reactions and a very brief review of their biochemistry and potential clinical value.

The synthesis of some amides of 1-amino-1-deoxyglucitol and correlation of their structures with the tinti-nofre sweetness model

Abstract A series of amides of 1-amino-l-deoxy-D-glucitol and 1-deoxy-l-methylamino-D-glucitol was prepared as possible sweeteners. A crucial feature was direct amidation without blocking and deblocking. Several strategies to induce sweetness were considered and a study of the correlation of these compounds with the Tinti-Nofre model was conducted.