Dietetic Purposes Research Articles

Preparation of Highly Pure n‐3 PUFA‐Enriched Triacylglycerols by Two‐Step Enzymatic Reactions Combined with Molecular Distillation

AbstractHighly pure n‐3 polyunsaturated fatty acids (PUFA)‐enriched triacylglycerols (TAG) have attracted considerable attention due to their nutritional benefits and pharmacological effects. In this study, an alternative approach to the conventional method for the synthesis of highly pure n‐3 PUFA‐enriched TAG by using a multi‐step process was reported. First, glyceride mixtures were synthesized through Novozym 435 [Novozymes A/S (Bagsvaerd, Denmark)] catalyzed esterification of n‐3 PUFA‐enriched FA and glycerol. Second, partial glycerides in the resulting glyceride mixtures were hydrolyzed to FA by immobilized partial glycerides‐selective lipase from Malassezia globosa. The purity of TAG reached 99.84% under the optimized conditions: buffer solution of pH 6.0, water content of 100% (w/w, with respect to the oil mass), enzyme loading of 120 U/g (U/w, with respect to oil mass) and reaction temperature of 30 °C. During hydrolysis, the immobilized SMG1‐F278N exhibited good reusability and TAG purity of over 94% was maintained after being used for six cycles. Subsequently, purification of TAG was accomplished by molecular distillation at low temperature (150 °C) and highly pure (99.85%) TAG with 88.73% n‐3 PUFA was obtained. The final glyceride mixtures with low acid, peroxide and anisidine value were promising products for medical and dietetic purposes. Compared with the conventional one‐step synthesis of n‐3 PUFA‐enriched TAG by enzymatic esterification or glycerolysis or the two‐step method by combined transesterification and ethanolysis, this improved process allows for higher purity of n‐3 PUFA‐enriched TAG and significant reduction in reaction time.

Вплив інгредієнтного складу на структурно-механічні властивості драглеподібних продуктів для спортсменів

Gel-like products are the prospective tendency in new products for special dietetic purposes research. An important characteristic of gel-like products’ quality that defines their suitability for usage according to intended purpose is structural and mechanical properties. They must be stable to the influence of temperature and certain ingredients, especially organic acids. The expediency of combining gelling agents pectin and xanthan gum to stabilize the structural and mechanical properties of gel-like products for athletes was investigated. It was established that addition of 0.05-0.2 % of xanthan gum increases the effective viscosity and limiting shear stress of gel-like products on 38-62 % and 13.7-25 % respectively. The structure of gel-like products only with pectin collapses with addition of organic acid, it is accompanied with a sharp decrease of effective viscosity on 30-37% and strength of the system on 33 – 47 %. Gel-like products with addition of xanthan gum maintain the structure; their rheological properties stay practically unchanged. Dependence between xanthan gum concentration and system strength change in the time of heating was established: increase of the xanthan gum concentration in the system causes decrease of the temperature influence on its strength. The results of the undertaken study can be used to develop formulations of gel-like food products for athletes.

Non-anthocyanin phenolic compounds and antioxidant activity of beverages obtained by gluconic fermentation of strawberry

Abstract Strawberry is widely harvested in Spain. It is a highly perishable fruit and surplus production may be used to produce innovative foods. This paper studies the influence of gluconic fermentation by Gluconobacter japonicus on the non-anthocyanin content and antioxidant activity of strawberry. A total of 43 non-anthocyanin phenolic compounds were identified. To the best of our knowledge, this paper reports five compounds for the first time in strawberry and its derivatives, tentatively identified as: monogalloyl diglucose, 5-hydroxy feruloyl hexose, dihydrokaempferol hexoside, kaempferol neohesperidoside and (−)chicoric acid. It was further observed that gluconic fermentation leaves in vitro antioxidant activity practically unchanged. Gluconic fermentation by Gluconobacter japonicus can be considered a potential tool for producing fermented beverages. It transforms glucose into gluconic acid, which allows diabetics to consume the drink, while maintaining bioactive compound concentration and antioxidant activity. Industrial relevance As strawberry is a highly perishable product, fruits spoil quickly, leading to substantial economic losses. Therefore, the transformation of strawberry surplus into new, longer-lasting products is a financially worthwhile solution for the industry and producers. Our gluconic beverages were elaborated by traditional process using exclusively strawberry as raw material easily transferable to industrial scale. The main innovation aspect relies on developing an innovative product, aiming to fulfill consumers demand who are permanently seeking for different taste and flavors. At the same time its composition in sugars (non-glucose, original fructose content) makes these products very suitable for dietetic purposes.

Enzymatic Synthesis of Extremely Pure Triacylglycerols Enriched in Conjugated Linoleic Acids

This work was objectively targeted to synthesize extremely pure triacylglycerols (TAG) enriched in conjugated linoleic acids (CLAs) for medical and dietetic purposes. Extremely pure CLA-enriched TAG was successfully synthesized by using the multi-step process: TAG was primarily synthesized by lipase-catalyzed esterification of CLA and glycerol and then the lower glycerides [monoacylglycerol (MAG) and diacylglycerol (DAG)] in the esterification mixtures was hydrolyzed to free fatty acids (FFAs) by a mono- and di-acylglycerol lipase (lipase SMG1), finally, the FFAs were further separated from TAG by low temperature (150 °C) molecular distillation. The operation parameters for the lipase SMG1-catalyzed hydrolysis were optimized using response surface methodology based on the central composite rotatable design (CCRD). The operation parameters included water content, pH and reaction temperature and all of these three parameters showed significant effects on the hydrolysis of lower glycerides. The optimal conditions were obtained with a water content of 66.4% (w/w, with respect to oil mass), pH at 5.7 and 1 h of reaction time at 19.6 °C. Under these conditions, the content of lower glycerides in the reaction mixture decreased from 45.2% to 0.3% and the purity of CLA-enriched TAG reached 99.7%. Further purification of TAG was accomplished by molecular distillation and the final CLA-enriched TAG product yielded 99.8% of TAG. These extremely pure CLA-enriched TAG would be used for in vivo studies in animals and humans in order to get specific information concerning CLA metabolism.

Investigations on potential dietetic effects of lactulose in pigs

Abstract Effects of lactulose (lac) as feed additive on chyme and feces quality in pigs (reared piglets: n = 10; fattening pigs: n = 20) were tested. Furthermore, fattening pigs were experimentally infected with Salmonella Derby (orally 2.6 × 10 8 cfu/pig, single dose infection on 1 day) to examine potential prophylactical effects. Pigs were fed a conventional diet ad libitum (in the control group without lac, in the experimental group including lac: 28.6/26.9 g lac/kg dry matter). In piglets and fattening pigs lac intake did not alter fecal dry matter (DM) content or feces pH. Contrary to findings in human beings only small amounts of lac reached the hindgut, although higher lac concentrations were measured in ileal chyme (in piglets: 10–40 g, in fattening pigs 40–70 g lac/kg DM of chyme). Lac ingestion led neither to increased concentrations of lactic acid or volatile fatty acids (vfa) nor to reduced pH data in chyme of small intestine, but in cecum and colon contents higher vfa concentrations (significant effects in piglets) were measured. Furthermore, lac ingestion resulted in reduced ammonia levels in small and large intestine contents. But no protective effects of lac ingestion were recognized when fattening pigs were infected orally with Salmonella Derby. Due to the fact that only parts of lac reach the hindgut there are doubts, whether lac can lead to comparable dietetic effects in pigs as known from human beings (laxation, forced elimination of bacteria a.s.o.). The obtained results in pigs underline the necessity of experimental studies in the target species before substances are used and recommended for dietetic purposes in feeding of pigs.

Assessing the antioxidant and pro-oxidant activity of phenolic compounds by means of their copper reducing activity

The antioxidant or pro-oxidant activity of some dietary phenolic compounds has been determined by their reducing activity over Fe3+ and Cu2+. The FRAP method has shown that phenolic acids exert a high reducing activity that give rise to a decrease in linoleic acid oxidation mediated by Fe3+, measured as TBARS. However, the reducing activity of phenolic compounds over Cu2+ leads to linoleic acid oxidation. Reducing capability against copper has been measured by a new approach called CRAI (Copper Reducing Activity Index), and results agreed with the degree of hydroxylation of the studied compounds. Sensibility and reproducibility of the method have been checked by measuring the inter-day and intra-day variation (1.08 and 1.89%, respectively). Possible pro-oxidant activity of phenolic compounds should be considered when the overall antioxidant activity in Cu naturally rich or Cu-enriched foodstuffs for dietetic purposes has to be evaluated.

Hydrolysates of skim milk

PurposeThe aim of this research is the evaluation of the profile of peptides isolated from skim milk hydrolysates.Design/methodology/approachFive hydrolysates were prepared using a protease from Aspergillus Oryzae (AO) separately or in combination with papain (PA) in different reaction times. The hydrolysates were fractionated by size‐exclusion HPLC and the rapid method of correct fraction area (CFA) was used for quantifying the peptides and free amino acids in the chromatographic fractions. The nutritional quality of hydrolysates is directly related to their di‐ and tripeptide contents, several reports show that the amino acid provided by these peptides are more quickly and completely absorbed than those from intact protein.FindingsThe results showed a nutritional similarity of the isolated action of AO and its combinations with PA, considering the peptide patterns produced, giving rise to 16 percent of di‐ and tripetides. Increasing the reaction time of the two enzymes led to poorer peptide profiles, while no change was achieved when the reaction time of only one enzyme (AO) in the combination was enlarged. Other hydrolytic conditions could be tested in order to improve the peptide profile of skim milk hydrolysates.Practical implicationsThe application of this study relates to the possibility of using these hydrolysates for preparing high nutritional formulation for dietetic purposes. The use of a technique allowing the fractionation of peptides according to their size as well as the use of the skim milk as protein source, instead of casein, which is very expensive in the developing countries, represents a novel approach.Originality/valueProvides an evaluation of the profile of peptides isolated from skim milk hydrolysates.

Expression of the sweet protein brazzein in maize for production of a new commercial sweetener

The availability of foods low in sugar content yet high in flavour is critically important to millions of individuals conscious of carbohydrate intake for diabetic or dietetic purposes. Brazzein is a sweet protein occurring naturally in a tropical plant that is impractical to produce economically on a large scale, thus limiting its availability for food products. We report here the use of a maize expression system for the production of this naturally sweet protein. High expression of brazzein was obtained, with accumulation of up to 4% total soluble protein in maize seed. Purified corn brazzein possessed a sweetness intensity of up to 1200 times that of sucrose on a per weight basis. In addition, application tests demonstrated that brazzein-containing maize germ flour could be used directly in food applications, providing product sweetness. These results demonstrate that high-intensity sweet protein engineered into food products can give sweetener attributes useful in the food industry.

FORMULATION AND QUALITY EVALUATION OF REDUCED SUGAR AND REDUCED CALORIE KAZANDIBI

ABSTRACT The production of kazandibi which is a milk pudding type of dessert for dietetic purposes was performed and the effects of various food additives on energy value, sensory and chemical components were investigated. A guar gum+xanthan gum (2.8+1.2) mixture besides rice milk and rice flour increased the textural quality whereas the artificial sweeteners aspartame+acesulfame K (0.25+0.25) together with small amounts of xylitol and fructose were effective in providing sufficient sweetness. Milk+cream aromas (1.5+0.3 and 1.5 + 0.5) had statistically significant (p < 0.05) effects in increasing flavor acceptability. The samples had higher protein contents (5%) and lower energy values (83kcal/100 g) than those of standard kazandibi and can be used both for diabetic and dietetic purposes.

Processes in ranking nutrients of foods in a food data base.

Depending on the type of user, it is possible that there are many purposes for retrieval of foods from a computerised nutrient data base. A Dietitian on one occasion may need to come up with a qualified assessment of foods in the process of diet construction so that the process of balancing nutrients for the diet takes less time. On another occasion the dietitian may want to recommend a food for a client which requires knowledge of the standing of that food with respect to one or more of its contents of nutrients. A dietitian is not able to memorise all the foods and their nutrient content. Moreover if the number of foods is many then the dietitian's ability to refer foods according to their standing may become impossible. Ranking foods with respect to their nutrient contents within a reasonable number could be very useful for dietetic purposes. This paper discusses the processes of ranking of foods as high, medium and low only, and proposes guidelines which can be referred to for rejecting inappropriate ranking schemes of foods. The proposed guidelines are based on the results of experiments which are included in this paper.

γ‐Linolenic acid concentrates from borage and evening primrose oil fatty acidsvia lipase‐catalyzed esterification

Abstractγ‐Linolenic acid (GLA, all‐cis 6,9,12‐octadecatrienoic acid) has been enriched from fatty acids of borage (Borago officinalis L.) seed oil to 93% from the initial concentration of 20% by lipase‐catalyzed selective esterification of the fatty acids withn‐butanol in the presence ofn‐hexane as solvent. The immobilized fungal lipase preparation, Lipozyme, used as biocatalyst, preferentially esterified palmitic, stearic, oleic and linoleic acids and discriminated against GLA, which was thus concentrated in the unesterified fatty acids fraction. In the absence of hexane, concentrate containing about 70% GLA was obtained. When the reaction conditions, optimized for borage oil fatty acids, were applied to fatty acids of evening primrose (Oenothera biennis L.) oil, concentrates containing 75% GLA were obtained. From both oils, GLA concentrates were prepared efficiently in short reaction times (1–3 h) at 30–60°C. The process can be applied for the production of GLA concentrates for dietetic purposes.

Characterization of enzymic sunflower protein hydrolyzates

Sunflower meal (SFM) proteins are denatured during the process of oil extraction, which greatly limits their functional and nutritional properties. Protein hydrolysates were prepared from defatted undehulled SFM by enzymatic hydrolysis using Kerase-a microbial neutral proteases hydrolysic agent. The resulting protein hydrolysates contained 78.9-84.8% protein and were highly soluble over a wide pH range (2-10). Their chemical composition, molecular weight distribution, and biological protein quality (protein efficiency ratio) were also studied. The properties of the resulting hydrolysates make them potentially useful in the food industry for dietetic purposes or as special food ingredients

Mass transfer in production of milk protein coprecipitates

During the last twenty years heat coagulation has become a more important technical procedure for the isolation of milk proteins because of its very efficient utilization of raw material. Experiments are reported to get approximation equations for the mass transfer in the production of milk protein coprecipitates from skim milk and mixtures of skim milk with rennet and acid whey by means of statistical planning and interpreting of experiments. Good exactness was reached. The coagula consist of casein fractions, whey protein fractions, calcium, and phosphates. The products are thermically rather stable, sensorically indifferent and contain water insoluble protein. They are suitable to improve the fat: protein ration of sausages, but also for the protein enrichment of other foods and for dietetic purposes.

The Nutritive Value of Marine Products: XII. Mineral Constituents of some Food Fishes of British Columbia

Ashes of composite samples of canned sockeye, pink and blueback salmon and canned pilchard were analyzed for Ca, Mg, Na, Ka P. Cl, S and traces of Cu and Mn. Comparison of the relative amounts of these elements with their concentration in sea water indicates selective absorption of Ca and K over Mg and Na respectively. The presence of Cu and Mn in trades is important for dietetic purposes.