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Spun soy fibers fractured by the tensile test, Warner-Bratzler shear, Kramer Shear Press and a modified Volodkevich wedge were examined with the scanning electron microscope. Fracture in the tensile test occurred almost always at a macrocavity, the weakest point in the fiber. Warner-Bratzler shear induced compression and flow at the zone of rupture, but not as markedly as in the case of the modified Volodkevich wedge. Fracture by the Kramer Shear Press was the closest to pure shear. Some of the exposed fracture surfaces revealed internal structures in the fibers such as macrocavities and distinct skin and core sections. The mechanism of rupture by these tests was more complex than expected.

The effect of high temperature, high humidity storage on cooking quality and physicochemical properties of dry, mature red kidney beans was evaluated over a storage period of 9 months. The rate of softening of beans during cooking, and the rate of dissolution of pectin during cooking followed apparent first-order kinetics and their apparent rate constants correlated highly with each other. The apparent softening rate constants decreased with increasing time of storage. The loss of cookability in mature bean seeds stored under high temperature-high humidity conditions probably results from a decrease in phytic acid phosphorus and alterations in the ratio of monovalent to divalent cations in the tissue.

Precooked, frozen omelets were analyzed for moisture loss, expressible moisture, shear-force, and sensory evaluation to determine water-holding capacity and- textural acceptability. Addition of 0.1% xanthan gum, application of moist heat in cooking, and cryogenic freezing with liquid carbon dioxide or nitrogen minimized moisture loss and shear force. Sodium. carboxymethylcellulose (CMC), pre-gelatinized tapioca starch and sodium tripolyphosphate additives performed satisfactorily, but omelets containing xanthan gum were consistently rated highest in sensory evaluation of several treatments, including fresh and untreated control omelets. Steaming omelets for five minutes combined with cryogenic freezing produced a desirable- omelet, requiring no additives. Steamed omelets were rated comparable to baked omelets in most sensory parameters.

Starch was isolated from fresh mango seed kernels. The effect of glucoamylase-α-amylase on the granule ultrastructure was evaluated by scanning electron microscope. Amylose and amylopectin were isolated and their molecular structures were studied, using enzymic methods, HPTLC, and gel permeation chromatography. The structure of amylopectin was similar to amylopectin of other starches. The shortest branch chain had 6 glucose units. Amylose had a s-amylolysis limit of 77%. In order to improve solution stability during debranching with pullulanase and chromatography, amylose was partially acetylated. The debranchin of the unmodified and modified amyloses produced a 15–25% decline in the limiting viscositiy number and a slight shift in the molecular size distribution. These results are consistent with the concept that a fraction of the amylose molecules have limited branching and that these branched chains contain a significant number of glucose units.

Freeze-etching was used to study the ultrastructure of waxy maize starch and acid-treated (0.5M HCl, 25°C, 24 hr) waxy maize starch. The outer surfaces of the untreated granules were smooth with a faint fibrillar pattern. Granule cross-fractures had a fine particulate appearance with some radially-oriented ridges. Internal cracks were evident. Starch granules soaked in acid developed surface pits. Areas of hydrolysis had a distinctive structure and occurred in restricted zones. The shape of the acid-treated starch granules remained unchanged. However, inner regions showed extensive ultrastructural changes and water infiltration. Freeze-etching revealed bands of alternating high and low water content which formed lamellae in a few granules.

Treatment of intact yeast cells with lytic enzymes, i.e. zymolase and lysozyme, markedly increased the release of nitrogen and proteins during incubation. The addition of pancreatin or pronase during incubation of cells with lytic enzymes caused the concurrent hydrolysis of the yeast proteins. The precipitable yeast protein at pH 4.5 decreased from 73 to 21% within 60 min. This procedure may be used for the commercial production of yeast autolysate.

Corn, waxy maize, potato and tapioca starches were cooked, subjected to different dehydration (oven-, freeze- and drum drying) and storage (frozen and refrigerated) conditions, and evaluated for pancreatic alpha amylase susceptibility. Dehydration reduced the enzyme susceptibility of all the starches. Oven drying had a greater effect than freeze- or drum drying. Frozen and refrigerated storage affected the susceptibility of corn, potato and tapioca starches but not waxy maize starch. Refrigerated storage had a greater effect than frozen storage. No differences were observed between constant and variable temperature frozen storage or between quick and slow freezing. The enzyme susceptibility did not change during 6 wk of storage.

Summary The ultrastructure of tapioca starch granules was studied using the freezeetching technique in an attempt to overcome the problems associated with the other methods of preparation for electron microscopy. A chemically-modified tapioca starch was also studied to ascertain whether chemical modification affected granule structure. Variations in fracture faces were observed in both modified and unmodified granules suggesting that organization within the granules was not homogenous. Particles were present on granule fracture faces. the size range of the particles was 4 to 10 nm in the unmodified and 6 to 15 nm in the modified granules. These observations were similar to those found by others in freeze-etched starch granules and must be considered to be of some structural significance. In contrast to the fracture face, the outer surface of the granules was smooth and particles were not evident.

LOW concentrations of porcine pancreatic or-amylase were utilized to partially hydrolyze dimethylsulfoxide-solubilized unmodified and modified waxy maize starches. Hydrolysis products were evaluated by viscometry and gel permeation chromatography methods. There was a pronounced drop in viscosity at low degrees of hydrolysis (< 1%) even though there was little change in the elution profile from Sepharose 4B. Hydroxypropyl starches were more resistant to or-amylase attack than the unmodified starch resulting in lower hydrolysis values and higher viscosities. Phosphate crosslinked starches with the same degree of hydrolysis as the unmodified starch had higher viscosities.

Sodium alginate was dispersed in iron chelate solutions and incubated for 10 min. The alginate was precipitated with acetone and the iron in the supernatant measured. Bound iron was calculated. The effects of pH, iron: alginate ratio, chelator, and competing cation on iron binding by alginate were determined. Binding increased as the pH decreased and as the iron:alginate ratio increased; the chelator used (EDTA, NTA, ascorbic acid, citrate) affected complexing. Binding decreased in the presence of calcium. In vitro iron availability studies indicated that alginate-iron complexes are disrupted during digestion.

Scanning Electron Microscopy (SEM) was used to study changes during the preparation of plasteins from egg albumin and corn zein protein isolates. This included an examination of protein particles that had been spray-dried, freeze-dried, hydrolyzed, and synthesized into plastein reaction products. Water holding capacity, oil binding capacity, and gel strength properties before and after modification are discussed. The study demonstrated that the quantity and quality of plastein products are dependent upon both the substrate and the enzyme used. A possible relationship is proposed between ultrastructural characteristics and actual functional performance of unmodified and modified proteins.

The adsorption of several iron compounds by unmodified and modified tapioca, corn and waxy maize starch was studied using transmission electron microscopy and atomic absorption spectrophotometry. Starch was incubated in an iron-containing solution. After centrifugation the amount of iron remaining in solution was compared to the original concentration to determine the quantity bound by the starch. Only iron in the form of colloidal ferric chloride showed significant binding. Long, cigar shaped structures, probably β-ferric oxyhydroxide crystals, were seen embedded in the surface of the granule. It is postulated that the oxygen and hydroxide groups surrounding the iron are responsible for binding to the carbohydrate. The study of the interaction of starch and metal compounds may lead to greater insight into methods of fortifying food products.

Differential scanning calorimetry (DSC) was used to study the effect of chlorine treatment of wheat flour on the heat of gelatinization of the wheat flour and starch. The DSC thermograms were corrected for heat capacity changes and thermal lag. An endothermic transition occurred in both flours and starches at a temperature commonly associated with starch gelatinization. The enthalpy (ΔH) for the starches was concentration dependent. The chlorine treatment did not affect significantly the transition temperatures nor enthalpies of either the flour or the starch isolated from it. Addition of sucrose delayed the onset of gelatinization and increased the ΔH for both treated and untreated wheat flours and starches.

Starch isolated from green banana fruit was hydrolyzed with pullulanase and β-amylase and the hydrolyzates fractionated on Sephadex G-50 and G-100. Debranching of the starch and it β-limit dextrin with pullulanase revealed that banana amylopectin had populations of d.p. 45 and d.p 15 chains in a molar ratio of 1:6. The average chain length of the debranched starch and the debranched β-limit dextrin was 26 and 10, respectively. The amylose content was 16%. Amylose prepared by selective leaching and by thymol complexation had β-amylolysis limits ≥ 92%.

The interaction between kappa and lambda carrageenan, and milk was examined utilizing three transmission electron microscopy procedures: thin sectioning, frozen thin sectioning and freeze-etching. Discrete fibrils were evident in the thin sectioned and freeze-etched gels whereas nonfibrillar linkages existed among casein micelles in frozen thin sectioned gels. Some micelles appeared to be connected to form small regular clumps in the lambda carrageenan-milk sols. Micelles in the kappa carrageenan-milk gels were aggregated into large irregular clumps. The microscopy method influenced the ultrastructural properties of the sols and gels.

The ultrastructural changes occurring during germination of spores of Penicillium roqueforti were examined using transmission electron microscopy on thin sections and freeze-etch replicas. The cell wall of the resting spore was composed of four distinct layers. The outermost layer ruptured and peeled off as the spores became swollen during the initial stages of germination. The germ tube, which emerged from the spore, had a thin cell wall which lacked the outer layers observed in the resting spore. As the germ tube transformed to mycelia it acquired extra outer layers so that the cell wall possessed three layers of material. Germinating spores were multinucleated. Membranous sacs and vesicles and endoplasmic reticulum were observed both in germinated spores and in mycelia. Freeze fracture techniques revealed that the surface of spores was covered with a layer of interwoven fibrils. This technique also confirmed the presence of distinct layers in the cell wall. The capacity of snail digestive enzymes to hydrolyze cell wall material was demonstrated.

Electron microscopy techniques were used to investigate the differences between thick and thin egg albumen at pH 7.4 and pH 9.0. There was no difference between the thick and thin raw albumens at either pH. The cooked thick and thin albumens at pH 7.4 were similar and were characterized by numerous large spherical osmiophilic structures. The cooked thick and thin albumens at pH 9.0 consisted of condensed particles which were embedded in a filamentous matrix. The thick albumen at pH 9.0 had smaller and more numerous asymetric particles than the thin albumen. The observed differences are attributed to changes in the heat lability of the various proteins and in the protein-protein complexes.

Raw material, raw emulsions and cooked frankfurters made from mechanically deboned poultry meat (MDPM) from the backs and necks of fryers, produced by three deboning machines (A, B, and C) and chopped for times varying from one and one half minutes to over 15 minutes were examined by light and electron microscopy. The raw MDPM from machines A and B appeared more dense and the fat globules smaller and more uniformly distributed than in the MDPM from machine C. Emulsion formation was found after only a short chopping period (one and one half to three minutes) and increasing chopping time did not always improve the appearance of the emulsion. For the material from machine A, the fat globules became smaller and more uniformly distributed, there was less effect on the emulsions from machine C and no effect from those from machine B.

Three gelatinized tapioca starches [unmodified (A), hydroxypropyl distarch phosphate (B) and hydroxypropyl starch (C)] were hydrolyzed by hog pancreatic α-amylase (EC 3.2.1.1 α-1,4-glucan 4-glucanohydrolase). Oligosaccharide constituents of the hydrolyzates were separated by thinlayer chromatography and quantified by spectrodensitometry. Glucose, maltose, maltotriose and maltotetraose were identified by cochromatography. Hydrolyzates from starches B and C had lesser amounts of the lower molecular weight oligosaccharides (G1—G4) than did those from starch A. The products of hydrolysis varied quantitatively with the degree of hydrolysis.

The growth of Streptococcus faecalis var liquefaciens caused the separation of egg yolk into upper and lower layers. Ultrastructure studies using transmission election microscopy showed that the upper layer was mostly low density fraction (LDF) with few electron dense particles. In contrast, the lower layer was mostly high density fraction (HDF). The separation factor caused aggregation of the HDF and openness of the structure of the matrix. The extent of incubation had a pronounced effect on the ultrastructure. Freeze-thaw treatment produced greater aggregation of HDF and more disruption of the LDF matrix, particularly in the lower layer.

The manner and rate of nuclear proliferation and accumulation in rat skeletal muscle was investigated using a model of induced permanent growth impairment in rats to gain additional insight into the regulation of skeletal muscle growth. Comparisons were made at 1, 21 and 175 d between control progeny and progeny of dams restricted during gestation and lactation to 50% the daily feed intake of ad libitum fed controls, followed by realimentation after weaning. Estimates of total satellite cells/muscle were lower (P less than .01) in soleus and extensor digitorum longus (EDL) of restricted progeny at 21 and 175 d. Estimates of total satellite cells/muscle increased nearly twofold between 21 and 175 d in the soleus and decreased slightly in EDL in both treatment groups. Satellite cell concentration expressed as a percentage of total muscle nuclei was not different between restricted and control progeny at either 1 or 175 d. However, while satellite cell percentages decreased about 50% between 1 and 21 d in controls, they remained at initial levels in restricted progeny. Incidence of satellite cells/muscle fiber (satellite cell concentration) decreased between 1 and 21 d in control soleus and EDL, but remained unchanged or was slightly higher in soleus and EDL of restricted progeny at 21 d. Incidence of satellite cells continued to decrease between 21 and 175 d in restricted and control EDL and restricted soleus, but was unchanged in control soleus. Incidence of myonuclei/fiber (myonuclei concentration) increased with age (P less than .005), was not affected by growth impairment either before or after realimentation and was higher (P less than .005) in soleus than EDL.(ABSTRACT TRUNCATED AT 250 WORDS)

We have examined the independent and combined effects of thyroxine (T4) and bovine growth hormone (bGH) on postweaning growth, satellite cell proliferation and accumulation of myonuclei in extensor digitorum longus (EDL) muscles in rats. Daily subcutaneous injections of T4 (1.5 micrograms/100 g BW), but not bGH (.25 IU/100 g BW) or T4 + bGH, resulted in elevated incidence of satellite cell nuclei and satellite cells per muscle fiber in transverse thin section, and a significantly (p less than .05) higher percentage of satellite cell nuclei and percentage satellite cells as a percentage of all muscle nuclei in transverse thin sections after one week of injections. The higher incidence of myonuclei per muscle fiber in transverse section in T4 injected rats at the end of the injection period (p less than .05) was interpreted to be the result of a higher concentration of satellite cells exhibiting normal or elevated mitotic activity during the early part of the injection period. The higher incidence of myonuclei per fiber was not caused by an increased mean fiber cross-sectional area in T4 injected rats. These histological observations relative to T4 injections were not accompanied by significantly greater weight, DNA content or estimates of total satellite cells per EDL muscle after either one or three weeks of hormone injections. These studies support the premise that T4 may be directly involved in the regulation of satellite cell proliferation and myonuclei accumulation, however, they do not support the premise that growth hormone exerts a similar influence during early muscle growth and development.

The presence of cardiolipin (diphosphatidyl glycerol) in lactating mammary tissue (cow and goat) was investigated. The tissue was separated into subcellular fractions by sedimentation; the identities of the fractions were confirmed by electron microscopy. Polar lipids recovered from the fractions, the whole tissues, and milks were analyzed by two-dimensional thin-layer chromatography and the percentages of cardiolipin were determined. The phospholipids of whole mammary tissue from the cow and goat contain 3-5% cardiolipin which is concentrated largely, if not exclusively, in the mitochondria. Although milk may on occasion have up to 1% cardiolipin in its phospholipids, some normal milks contain less than 0.15%. Since tissue contains 20-30 times the amount (mg/g) of phospholipids in milk, the quantitative ratio of tissue to milk cardiolipin is several hundred to one. We interpret this to mean that the mechanism of milk secretion is highly selective and insures retention of mitochondria within the cell even though they are decidedly smaller than milk fat globules which are continuously secreted. Our findings substantiate the conception that there is very little disintegration of the cell or disruption of the plasma membrane during milk secretion. The fatty acids of cardiolipin from lactating mammary tissue of cow, goat, and pig are highly unsaturated; they contain 50% or more octadecadienoic acid.