Potato and soy peptides alter caecal fermentation and reduce serum non‐HDL cholesterol in rats fed cholesterol

We examined the effect of potato peptides (PPC) in rats fed a cholesterol‐enriched diet, in comparison with two cholesterol‐enriched diets containing soy peptides (SPC) or casein (CNC), and a cholesterol‐free diet containing casein (CN) for 4 weeks. The serum non‐high‐density lipoprotein (HDL) cholesterol level was lower in the PPC‐ (–18.39%) and SPC‐fed (–32.76%) groups (p <0.05) than in the CNC‐fed group at the end of the feeding period. The low‐density lipoprotein receptor mRNA level in the PPC‐fed group, and cholesterol 7α‐hydroxylase and scavenger receptor class B type 1 mRNA levels in the SPC‐fed group, were higher (p <0.05) than in the CN‐ and CNC‐fed groups. Faecal neutral sterol and caecal short‐chain fatty acid concentrations in the PPC‐ and SPC‐fed groups were higher (p <0.05) than in the CN‐ and CNC‐fed groups. The faecal total acidic sterol concentration was higher in the SPC‐fed group than in the CN‐ and PPC‐fed groups. Caecal anaerobe and Bifidobacterium populations were higher (p <0.05) in the PPC‐ and SPC‐fed groups than in the CN‐fed group. This study suggests that potato peptides, as soy peptides, alter caecal fermentation and steroid absorption and reduce the serum non‐HDL cholesterol level in rats fed cholesterol.     

Dietary effect of gamma-linolenic acid on the lipid profile of rat fed erucic acid rich oil

This study evaluated the effects of dietary supplementation of gamma-Linolenic acid (18:3n-6, GLA) on the lipid profile of serum and other tissues of rats fed erucic acid (C22:1) rich oil like mustard oil. The rats were fed diet containing 20% mustard oil as erucic acid rich oil and 20% groundnut oil as dietary fat. These groups were kept as reference groups. Another group fed diet containing 20% fat to which evening primrose oil as a source of GLA was blended with mustard oil and groundnut oil at 5% level. The feeding experiment was done for 4 weeks. In another set mustard oil fed group was kept as control while the experimental group was fed evening primrose oil as a source of GLA blended with mustard oil at 2.5% level. The feeding experiment was carried out for 12 weeks. The other dietary components remained same for all the groups. After the scheduled feeding period, it was found that there was no significant change in weight gain, food intake and food efficiency ratio. It was found that dietary GLA resulted in significant decrease in serum triglyceride (TG) and very low density lipoprotein (VLDL) cholesterol and significant increase in high density lipoprotein (HDL) cholesterol in serum in the experimental group. In liver total cholesterol (TC) is significantly higher and in heart and liver TG is significantly lower in GLA fed group.     

Crambe seed processing. improved feed meal by soda ash treatment

Crambe seed, like rapeseed, is characterized by having thioglucosides and perhaps other antigrowth factors that diminish feed value and palatability. A soda ash cooking process was developed that modifies the thioglucosides in crambe meal and significantly improves its feeding value. Destruction of the undesirable thioglucoside fraction of the meal was demonstrated, not only by paper Chromatographic changes but also by negative results in tests which were based on conversion of the thioglucoside to thiooxazolidone. Sodium carbonate, added at a level of 1.4% (whole seed basis), destroys both the goitrin precursor,epi-progoitrin thioglucoside, and the ultraviolet-absorbing compounds in the meal, at least one of which is associated with bitterness. Animal-feeding tests demonstrated the improved palatability and nutritional quality of the meal. Presented in part at the AOCS Meeting, Philadelphia, October 1966. Journal Series, Nebraska Agricultural Experiment Station. No. Utiliz. Res. Dev. Div., ABS, USDA.     

Digestibility and nutritional value of crude oil from three amaranth species

Oils from a selection ofAmaranthus caudatus, A. hypochondriacus andA. cruentus were extracted with hexane. The crude oils were analyzed for acid value, saponification and iodine number, and were included in basal casein diets for rat studies at 5 and 10% levels to replace equal amounts of refined cottonseed oil. The oils fromA. cruentus andA. hypochondriacus were similar in the oil properties studied and different fromA. caudatus. At either 5 or 10% food intake levels, weight gain and PER were not statistically different from values reported for cottonseed oil. True digestibility of amaranth oil was lower than that of cottonseed oil.A. cruentus oil gave the lowest digestibility. Oil levels induced statistical differences in food intake and digestibility. Oils fromA. caudatus, A. hypochondriacus and cottonseed induced similar serum cholesterol levels, while oil fromA. cruentus gave statistically higher values. Hemoglobin, hematocrit and serum proteins were similar among all groups. Microscopic analysis of the organs of the rats revealed some changes that were also found in cottonseed oil-fed rats. It was concluded that crude amaranth oil has lower digestibility than cottonseed oil, but that it is not responsible for growth-depressing effects when the seed is fed raw as compared to processed materials.     

Liver and serum lipids and lipoproteins of rats fed 5% L-lysine

Soybean protein and casein supplemented with 1% Arg were compared for their ability to prevent fatty livers caused by excess dietary Lys. The concentrations of serum lipids and lipoproteins of rats fed 5% Lys and having vatty livers were also compared with those of rats fed the identical diet but lacking fatty livers when killed. The total liver lipids, triglycerides and cholesterol of rats fed 15% casein +5% Lys were 3.9, 12.4 and 2 times control values, respectively. Rats fed 5% Lys +1% Arg or 5% Lys with 15% soybean protein had liver lipid concentrations similar to controls fed no supplemental Lys. Serum total lipids, triglycerides, cholesterol, phospholipids and free fatty acids also did not change, and serum ketone bodies were slightly elevated with Lys feeding whether the rats had fatty livers or not. The concentrations of circulating HDL were slightly depressed in all rats fed 5% Lys while LDL were significantly elevated, particularly in rats without fatty livers. Serum VLDL did not change with 5% dietary Lys. Overall, excessive dietary Lys caused fatty livers which were prevented by varying the diet or length of feeding. Excess Lys feeding altered lipoprotein metabolism shown by decreased serum HDL and a substantial elevation in LDL. The latter was more apparent when the fat accumulation in liver was less severe or absent. The data suggest that the fatty liver from Lys excess is probably unrelated to increased fat mobilization from storage, decreased fat oxidation or to a major block in the transport of triglycerides from the liver to the circulation.     

Detoxification of castor seed meal by interaction with sal seed meal

Castor (Ricinus communis) seed meal was detoxified by a novel method of wet mixing with sal (Shorea robusta) seed meal so that the toxic constituents of castor seed meal were neutralized by tannins, the toxicants present in the sal seed meal. The resulting product was innocuous, as revealed in the feeding studies in rats. The nutritional benefit of the treated material is improved by synergistic action of a protein such as casein. The aqueous extract of castor seed meal produced a smooth-muscle stimulant effect, whereas this effect was not observed with the extract from treated meal. This is a new concept of neutralization of two toxins by each other in two seed meals. The method can be employed to investigate the suitability of such a processed seed meal as an animal feedstuff ingredient.     

Mustard seed processing: Simple methods for following heat damage to protein meals

Processed mustard seed contains a considerably higher content of reducing sugar than other oilseeds. During processing, the natural reducing sugar is supplmented with glucose released by enzyme hydrolysis of the thioglucoside, and this total content reaches a value of more than 3% of the defatted mustard meal. This quantity of reducing sugar in mustard seed is three times more than that in soybean meal. Consequently, the browning reaction, which degrades protein, presents a greater problem in processing oilseeds containing thioglucosides than oilseeds free of thioglucosides. In developing the processing of mustard seed, the degree of heat treatment given the protein meals had to be determined. Several indirect methods were developed for following the effects of heat treatment on protein quality. Nitrogen solubility index, optical density of aqueous extracts, and reducing sugar content correlated well with degradation of heat-labile amino acids, such as lysine, arginine, and histidine, and gave an index of protein quality. Presented at the AOCS meeting in Minneapolis, 1963. A laboratory of No. Utiliz. Res. and Dev. Div., ARS, USDA.     

Nutritional Aspect of Sal Meal

A nutritional study was carried out with white albino rats fed treated and untreated sal meal at 30% level in diet for 3 months. The effect of high protein level in diet on rats fed 30% untreated sal meal was also investigated. rats fed 30% sal meal with intact tannin showed abnormal lipid spectrum and also protein content in both liver and serum while the lipid spectrum and protein content in liver and serum of rats fed 30% treated sal meal were comparable to that of control rats. The toxic effect of sal meal was reduced to some extent when the protein level was improved in diet.     

Conversion of Canola Meal into a High-Protein Feed Additive via Solid-State Fungal Incubation Process

The study goal was to determine the optimal fungal culture to reduce glucosinolates (GLS), fiber, and residual sugars while increasing the protein content and nutritional value of canola meal. Solid‐state incubation conditions were used to enhance filamentous growth of the fungi. Flask trials were performed using 50 % moisture content hexane‐extracted (HE) or cold‐pressed (CP) canola meal with incubation for 168 h at 30 °C. Incubation on HE canola meal Trichoderma reesei (NRRL‐3653) achieved the greatest increase in protein content (23 %), while having the lowest residual levels of sugar (8 % w/w) and GLS (0.4 μM/g). Incubation on CP canola meal Trichoderma reesei (NRRL‐3653), A. pullulans (NRRL‐58522), and A. pullulans (NRRL‐Y‐2311‐1) resulted in the greatest improvement in protein content (22.9, 16.9 and 15.4 %, respectively), while reducing total GLS content from 60.6 to 1.0, 3.2 and 10.7 μM/g, respectively. HE and CP canola meal GLS levels were reduced to 65.5 and 50.7 % by thermal treatments while solid‐state microbial conversion further reduced GLS up to 99 and 98 %, respectively. Fiber levels increased due to the concentration effect of removing oligosaccharides and GLS.     

The influence of protein and carbohydrate type on serum and liver lipids and lipoprotein cholesterol in rabbits

The non-lipid portions of semi-synthetic diets appear to be important determinants of hypercholesterolemia and atherosclerosis in the rabbit. Serum and liver lipid concentrations were determined in rabbits which had been pair-fed various protein (casein or soy protein isolate) and carbohydrate (sucrose or dextrose) sources as part of low fat, low cholesterol, semi-synthetic diets. It was verified that caseincontaining diets render rabbits hypercholesterolemic, while soy protein caused a degree of hypocholesterolemia. Additionally, sucrose, when fed in conjunction with casein, appears to augment this hypercholesterolemic effect. The distribution of total cholesterol among lipoprotein subclasses was increased in both the intermediate density lipoprotein (IDL) (1.006–1.019 g/ml) and low density lipoprotein (LDL) (1.019–1.063 g/ml) fractions and decreased in the high density lipoprotein (HDL) (1.063–1.21 g/ml) fraction when casein is fed. Soy protein feeding caused relatively more cholesterol to appear only in the IDL fraction when compared with commercial chow fed rabbits. Reasons for these differences may involve the saturation or suppression of endogenous lipoprotein hepatic receptors.     

Isopropanol as a solvent for extraction of cottonseed oil

Phase equilibrium data for the system; cottonseed oil-isopropanol-water were determined at 30°C. and compared with data for the system; cottonseed oilethanol-water. The relative phase distribution of fatty acids and cottonseed oil in mixtures with isopropanol and water was studied under varying conditions of water and fatty acid concentrations. These tests showed the fatty acids to be highly concentrated in the alcohol-water phase. Flaked cottonseed meats were extracted in continuous extraction apparatus with 91% isopropanol, 99% isopropanol, and mixtures of commercial hexane and isopropanol. Analytical data on the extractions show that 91% isopropanol is an efficient solvent for extracting active gossypol along with the oil. Rat and swine feeding tests of the isopropanol extracted meal showed it to be highly superior to hydraulic meal as a source of protein. A method was developed for treatment of the cottonseed-isopropanol miscella by liquid-liquid extraction to separate purified oil and fatty acid fractions from other materials in the extract.     

Egg ovomucin attenuates hypercholesterolemia in rats and inhibits cholesterol absorption in Caco-2 cells

This experiment was designed to evaluate the effect of casein or ovomucin (OV) on the micellar solubility of cholesterol and the taurocholate binding capacity in vitro. We also evaluated the effects of casein or OV on cholesterol metabolism in rats and Caco-2 cells. OV has a significantly greater bile acid-binding capacity than that of casein in vitro. Micellar cholesterol solubility in vitro was significantly lower in the presence of OV compared to casein. The cholesterol micelles containing OV significantly suppressed cholesterol uptake by Caco-2 cells compared to the cholesterol micelles containing casein. Consistent with these in vitro findings, OV-feeding significantly increased the fecal excretion of bile acids or cholesterol compared with casein-feeding. Serum total cholesterol was significantly lower in rats fed OV than in those fed casein. The concentrations of total lipids in liver were significantly lower in the OV-fed group compared with the casein group. These results suggest that the suppression of cholesterol absorption by direct interaction between cholesterol mixed micelles and OV in the jejunal epithelia is part of the mechanism underlying the hypocholesterolemic action of OV. OV may also inhibit the reabsorption of bile acids in the ileum, thus lowering the serum cholesterol level.     

Isopropyl Alcohol Extraction of De‐hulled Yellow Mustard Flour

Vegetable oils are typically extracted with hexane; however, health and environmental concerns over its use have prompted the search for alternative solvents. Mustard oil was extracted with isopropyl alcohol (IPA) to produce an IPA‐oil miscella suitable for industrial applications. Single‐stage extraction resulted in 87.6 % oil yield at a 10:1 (v/w) IPA/flour ratio. Multiple‐stage extraction resulted in higher extraction efficiency with lower IPA use. Four‐stage cross‐current extraction at an IPA/flour ratio of 2:1 (v/w) per stage resulted in 93.7 % oil yield. At 45 °C, a 91.5 % oil yield was achieved with three‐stage extraction using a 2:1 (v/w) IPA/flour ratio. Any changes to the pH of the mixture resulted in reduced oil yield. Water also reduced the extraction efficiency. The azeotropic IPA solution containing 13 % water extracted ~40 % less oil than did dry IPA in both single and multiple‐stage extractions. Some polar compounds were also extracted, including sugars; however, protein extraction was negligible. The protein left in the extracted meal was not degraded or lost during the extraction. The results suggest that IPA is an excellent solvent for mustard oil, but water content exceeding 5 % in the solvent adversely affects the oil extraction and reuse of the IPA.     

Preparation of colorless sunflower protein products: Effect of processing on physicochemical and nutritional properties

A comparison was made of the different technological treatments for the preparation of colorless sunflower protein products from the viewpoint of the effect of processing conditions on the extraction yield of nitrogen and lipid, chemical, physicochemical and nutritional properties of the processed products. The technological treatments comprised soaking dehulled seeds in dilute citric acid or sodium bisulfite solution and washing the defatted meal with the respective solution. The defatting process was carried out with hexane or azeotrope (hexane/ethanol). Nitrogen and lipid recovery was slightly greater for hexane defatted products than for azeotrope defatted products. About 21.4% of the phenolic compounds of the sunflower seeds were bound to the proteins of the seeds before processing and therefore could not be eliminated by the aqueous extraction. Aqueous extraction of phenolic compounds was limited for full fat seed. The free phenolic compounds were very stable in acid medium but sensitive to oxidation in alkaline medium and had no significant effect on in vitro enzymatic proteolysis and growth inhibition of rats. Lysine and the bound phenolic compounds were the critical factors responsible for inhibition of enzymatic proteolysis and reduced growth of rats. The diet containing whole seed meal presented a low protein efficiency ratio (PER) value. Citric acid, a chelating agent, proved to be an antioxidant as effective as sodium bisulfite; the products obtained by citric acid treatment had a visually whiter color than those processed by sodium bisulfite.     

Nutritional quality of detoxified karanja (Pongamia glabra) oil

Fatty acid composition of crude karanja (Pongamia glabra) oil resembles groundnut oil but it contains some toxic phenolic compounds, like karanjin and pongamol. Removal of these phenolic compounds prior to edible use is therefore important. Nutritional quality of the refined karanja oil (detoxified by isopropanol extraction, bleaching and deodorization) has been investigated in rats by feeding this oil where groundnut oil has been used as control. These two oils were fed at a 20% level in each group in an 18% protein and 55% starch diet for six weeks. The refined karanja oil was observed to be utilized in an identical manner to that of groundnut oil as revealed by growth of rats, food efficiency ratio and the lipid profile of serum and liver tissues.     

Effect of garlic (Allium sativum linn) on serum lipoproteins and lipoprotein cholesterol levels in albino rats rendered hypercholesteremic by feeding cholesterol

The hypocholesteremic activity of garlic was tested by incorporating freeze-dried garlic powder at 0.5, 1.0, 2.0 and 3.0% levels in an atherogenic diet fed to rats. It was observed that 0.5 and 1.0% levels were not effective whereas the other 2 levels were. The group fed 2.0% garlic powder had much lower serum cholesterol level than the one fed 3%. The increased levels of low density lipoproteins (LDL) and LDL-cholesterol in rats fed the atherogenic diet were partly reversed in rats receiving a supplement of 2% garlic powder. On a cholesterol-containing diet, high density lipoproteins (HDL) and HDL-cholesterol levels were decreased. Inclusion of garlic powder in the atherogenic diet enhanced the percentage of HDL whereas no change was observed in HDL cholesterol levels. Commercial garlic pearls (equivalent to 0.15% garlic powder in the diet) produced a significant decrease in serum and liver cholesterol levels in rats fed the atherogenic diet. On the other hand, asafoetida at 1.5% level failed to reduce the serum cholesterol levels in the cholesterol-fed rats.     

<Emphasis Type="Italic">Lesquerella fendleri</Emphasis> protein fractionation and characterization

Lesquerella fendleri is a promising new crop whose seed contains hydroxy FATG with potential industrial uses as well as substantial amounts of valuable gums. The defatted L. fendleri seeds also contain more than 30% protein. The objective of this study is to process and characterize this protein component for possible future uses in food. Hexane-defatted seed has more than 30% protein content. Defatted lesquerella meal was extracted sequentially with 0.5 M sodium chloride (2×), water, 70% ethanol, and 0.1 N sodium hydroxide (2×). Each sodium chloride extract was dialyzed against deionized water and centrifuged to separate the water-soluble fraction (albumin) from the salt-soluble fraction (globulin) before freeze-drying. The ethanol extract and the neutralized sodium hydroxide extracts (glutelin) were dialyzed against water and freeze-dried. Albumin had the highest proportion of lysine and sulfur amino acids per 16 g nitrogen among all the fractions analyzed. Glutelin and globulin accounted for the highest amount of protein nitrogen. SDS-PAGE of the reduced albumin, globulin, and glutelin showed the presence of several protein bands with M.W. ranging from 7 to 98 kDa. Nitrogen solubility of defatted lesquerella meal from pH 2 to 12 indicated a solubility minimum of 15% around pH 4.2 and a solubility of 75% at pH 11.5. Nonprotein nitrogen of defatted meal was 12% of total nitrogen. Defatted lesquerella meal has the potential for food use based on good nitrogen solubility and good amino acid composition.     

Cholesterolemic effects of the lysine/arginine ratio in rabbits after initial early growth

The lysine/arginine ratio has been directly associated with serum cholesterol levels. Male, New Zealand rabbits with a mean weight of 2.1 kg were fed, ad libitum, one of three diets containing 14% vegetable oil and 20% protein from casein, soy or almonds with lysine/arginine ratios of 2.2, 0.9, or 0.3, respectively. At the end of three weeks for phase 1, the serum cholesterol level of the casein group (154 +/- 25 mg/dl, mean +/- SD) was twice the level and significantly greater (p less than 0.02) than either of the plant protein groups (soy 70 +/- 7, almond 78 +/- 6 mg/dl). During phase 2, the almond diet was supplemented with L-lysine to increase the lysine/arginine ratio from 0.3 to 3.0 while casein remained as the high, and soy the low lysine/arginine ratio control diets. Serum cholesterol levels remained high for the casein, and low for the soy groups, while lysine supplementation significantly increased (p less than 0.05) the serum cholesterol level in the almond protein group (from 78 +/- 6 to 101 +/- 10), but not greater than the casein group. Growth was similar for rabbits fed soy or casein diets throughout the study, but lower (p less than 0.02) for the almond group. Thus, growth rate was not related to the effect of dietary protein on levels of serum cholesterol. While there is a direct relationship between hypercholesterolemia and the absolute amount of dietary lysine and with the lysine/arginine ratio, the data suggest that this is only a partial explanation for the effect of proteins on the control of serum cholesterol levels.     

Separate effects of dietary protein and fat on serum cholesterol levels: another view of amino acid content of proteins

Casein or soy protein with vegetable or animal fat were used to determine the dietary protein or fat effects and their possible interaction on serum cholesterol levels. Young, male New Zealand white rabbits with a mean weight of 2.1 kg were divided into groups of six and fed one of four different diets containing 20% of the calories as protein, 30% as fat (according to dietary guidelines for the United States) and 50% as carbohydrate. The diets contained casein or soy (lysine/arginine ratio = 2.2 or 0.9, respectively) as the protein sources with fat from either almond oil or butter. There was no significant difference in weight gain among the diet groups. Total serum cholesterol level was highest among animals fed the diet containing butter with casein (177 +/- 25 mg/dl) or soy protein (189 +/- 50 mg/dl), it was intermediate in animals fed the vegetable oil with casein (121 +/- 14 mg/dl), and lowest in the soy protein with vegetable oil group (58 +/- 12 mg/dl). There was a significant difference in serum cholesterol levels due to the protein effect when vegetable oil was used (p less than 0.05) but not with butter. There was also a significant fat effect on serum cholesterol when the diet contained soy protein (p less than 0.005) but not when the protein was casein. No significant interaction was observed between the dietary fat and protein sources on serum cholesterol levels, which suggests that dietary protein and fat independently affect the levels of serum cholesterol. Thus, dietary protein has a significant effect on serum cholesterol levels and may be a factor in the low levels of serum cholesterol observed among vegetarians and in humans of Third World countries where the diets is primarily of vegetable origin.     

Studies on Nutritional Quality of Interesterified Fat Products

The nutritional quality of the fat products with melting range 36° to 37°C having been prepared from non-traditional oils like mowrah (Madhuca latifolia), ricebran (Oryzasativa) containing sal (Shorea robusta) and cottonseed (Gossypium hirstum) mixed with sal by interesterification (randomisation) were examined with rats and compared with that of “Vanaspati”, produced by hydrogenation of mixtures of liquid oils and used exclusively as a substitute of ghee (butter fat) in India. The average food intake, body weight gain, food efficiency ratio, weight of different organs, total lipid content of serum, liver, heart and kidney were similar in all the cases. Serum triglyceride levels were quite low in case of interesterified fats fed rats though total and free cholesterol levels were not significantly different. Serum phospholipid levels were slightly higher in case of the interesterified fats fed rats. Total and free cholesterol, phospholipid and triglyceride content of liver, kidney and heart were similar for the four dietary groups of rats. Serum lipids and liver lipids contain more polyunsaturated fatty acids when rats were raised on various interesterified fats in place of hydrogenated fat product “Vanaspati”.