ACTA Scientiarum Polonorum - Technologia Alimentaria News en (c) Wydawnictwo Uniwersytetu przyrodniczego w Poznaniu Antioxidant activities of leaf galls extracts of Terminalia chebula (Gaertn.) Retz. (Combretaceae)

Background. Free radicals are implicated in several metabolic diseases and the antioxidant therapy has gained an utmost importance in the treatment. The medicinal properties of plants have been investigated and explored for their potent antioxidant activities to counteract metabolic disorders. In this study, the chemical composition and free radical scavenging potential of leaf gall extracts (ethanol, petroleum ether, chloroform and aqueous) of Terminelia chebula is evaluated, which is extensively used in the preparation of traditiona medications to treat various metabolic diseases.
Material and methods.
The presences of phenolics, fl avonoids, triterpens, saponins, glycosides, phytosterols, reducing sugars were identifi ed in the extracts according to standard procedures. The free radical scavenging activities of the extract were also analysed by standard procedures.
The methanol extract had the highest total phenolic and fl avonoid content. The antioxidant activities of leaf gall extracts were examined using diphenylpicrylhydrazyl (DPPH), Super oxide radical scavenging, Hydroxyl scavenging and ferric reducing power (FRAP) methods. In all the methods, the ethanolic extract showed higher free radical scavenging potential than all the other extracts.
As the higher content of both total phenolics and fl avonoids were found in the ethanolic extract, so the signifi cantly high antioxidant activity can be positively correlated to the high content of total polyphenols/fl avonoids of the ethanol extract. The results of this study confi rm the folklore use of T. chebula leaves gall extracts as a natural antioxidant and justify its ethnobotanical use. Further, the results of antioxidant properties encourage the use of T. chebula leave gall extracts for medicinal health, functional food and nutraceutical applications.

Eff ect of incubation time, inoculum size, temperature, pasteurization time, goat milk powder and whey powder on ACE inhibitory activity in fermented milk by L. plantarum LP69

Background. Angiotensin I converting enzyme (ACE) plays an important physiological role in regulating hypertension. Lactic acid bacteria are known to produce ACE inhibitory peptides which can lower hypertension during fermentation.
Methods. The effect of incubation time (0~36 h), inoculum size (3, 4, 5, 6 and 7%, v/v), temperature (25, 30, 35, 40 and 45°C), sterilization time (5, 10, 15, 20 and 25 min), concentration of goat milk powder (8, 10, 12, 14 and 16%, w/v) and whey powder (0.5, 0.6, 0.7, 0.8 and 0.9%, w/v) on ACE inhibitory peptides fermented from goat milk by Lactobacillus plantarum LP69 was investigated using single factor experiment.
Results. The optimal incubation time, inoculum size, temperature, pasteurization time, goat milk powder and whey powder in fermented milk by L. plantarum LP69 was 14 h, 3.0%, 35°C, 20 min, 14% and 0.70% for ACE inhibitory activity and 22 h, 3.0%, 40°C, 25 min, 16% and 0.60% for viable cell counts, respectively.
Conclusion. The incubation time, inoculum size, temperature, pasteurization time, goat milk powder and whey powder had a signifi cant infl uence on ACE inhibitory activity in fermented milk by Lactobacillus plantarum LP69, the results are benefi cial for further screening of main factors by using fractional factorial designs.

Effects of sugar alcohol and proteins on the survival of Lactobacillus bulgaricus LB6 during freeze drying

Background. Lactobacillus bulgaricus LB6 is a bacterium which was selected in the commercial yoghurt with high angiotensin converting enzyme (ACE) inhibitory activity. Preparation of concentrated starter cultures via freeze drying is of practical importance to dairy and food industries.
Material and methods. We optimized the optimal sugar alcohol and proteins for Lactobacillus bulgaricus LB6 during the process of freeze drying using a Plackett-Burman design. In our initial tests survival rate and the number of viable cells were associated with the type of lyoprotectant used and so our optimization protocol focused on increasing survival rate. Substances that had previously had a protective effect during freeze drying were investigated, for example: mannitol, sorbitol, xylitol, meso-erythritol, lactitol, whey protein isolate 90, bovine serum albumin, and whey protein concentrate 80 and soy protein isolate 70.
Results. We found that the optimum sugar alcohol and proteins for survival of Lactobacillus bulgaricus LB6 were whey protein concentrate (p = 0.0040 for survival rate), xylitol (p = 0.0067 for survival rate) and sorbitol (p = 0.0073 for survival rate), they showed positive effect (whey protein concentrate and sorbitol) or negative effect (xylitol).
Discussion. The effectiveness of three chosen sugar alcohols and protein implied that they could be used as lyoprotectant for Lactobacillus bulgaricus LB6 in the further research, the optimal composition of sugar alcohol and protein for the lyoprotectant use must be established.

Proteolysis in tempeh-type products obtained with Rhizopus and Aspergillus strains from grass pea (Lathyrus sativus) seeds

Background. Tempeh is a food product obtained from legumes by means of solid-state fermentation with Rhizopus sp. Our previous research proved that mixed-culture inoculum may also be successfully applied. The objective of present research was to study the proteolytic activity of R. microsporus var. chinensis and A. oryzae during tempeh-type fermentation of grass pea seeds, and the effect of inoculum composition on the protein level and in vitro protein bioavailability in products.
Material and methods. Fermentation substrate were soaked and cooked grass pea seeds. Material was mixed with single- or mixed-culture inoculum, and incubated in perforated plastic bags at 30°C for 32 hrs. In the products, the proteolytic activity (pH 3, 5 and 7), glucosamine, total protein and free amino acids levels, as well as protein in vitro bioavailability and degree of protein hydrolysis were obtained.
Results. The signifi cant correlation was found between glucosamine content and proteolytic activity in grass pea seeds fermented with Rhizopus or Aspergillus. The activities of Rhizopus proteases were higher than Aspergillus ones, which corresponded with the degree of seed protein hydrolysis. Both strains showed the highest activity of protease at pH 3. Tempeh made with pure culture of Rhizopus had 37% protein of 69% in-vitro bioavailability. Mixed-culture fermentation improved nutritional parameters of products only when the dose of Aspergillus spores in the inoculum was equal and lower than that of Rhizopus. This process resulted in higher in-vitro bioavailability of protein, slightly more effi cient protein hydrolysis and higher level of free amino acids, as compared to standard tempeh.
Conclusions. The activity of A. oryzae in tempeh-type fermentation is benefi cial as long as it does not dominate the activity and/or growth of Rhizopus strain.

Arachidonic acid production by Mortierella alpina using raw crop materials

Background. Arachidonic acid (ARA) is one of the three essential fatty acids, and it is important for human body to keep healthy and is widely used. At present, expensive materials such as glucose and yeast extract are generally reported to be optimal for ARA production. A new cost-effective fermentation process including cheaper material for ARA production is of great signifi cance.
Material and methods. Feasibility of using corn meal and powdered soybean for fungal growth and lipid accumulation was evaluated by means of single factor test. N-hexadecane concentration was optimized, and the effect of temperature on biomass and ARA content was examined.
Results. Mortierella alpina made better use of the aforementioned material as carbon and nitrogen sources for both hyphae growth and ARA production compared with glucose and yeast extract. Maximal levels of 10.9 g/L ARA and 26.1 g/L total lipids were obtained when 66 g/L corn meal, 54 g/L soybean meal and 6% (v/v) n-hexadecane were supplemented. A temperature-shift strategy involved three steps, namely, 30°C (3 days) – 25°C (4 days) – 20°C (4 days), which further improved ARA production by 24.7%.
Conclusion. Several factors such as carbon and nitrogen sources, temperature and dissolved oxygen had great infl uence on biomass and microbial oil production. Mortierella alpina preferred corn and soybean meal compared with glucose and yeast extract, which would surely alleviate the high cost of ARA production. Based on this study, the new process is both low cost and practicable.

Stevia rebaudiana Bertoni – chemical composition and functional properties

Sweetleaf (Stevia rebaudiana Bertoni), currently investigated by many researchers, has been known and used for more than a thousand years indigenous tribes of South America, who called it “kaa-hee” (“sweet herb”). Thanks to its chemical composition and processability sweetleaf may be an alternative for synthetic sweeteners. Nutritional and health-promoting aspects of Stevia rebaudiana are presently being studied in many research centres. The aim of this study is to present nutritional and health-promoting value of the still-little known sweetleaf.

Nutritional value of raw pork depending on the fat type contents in pigs feed

Background. The research aimed to assess the nutritional value of raw pork meat obtained from pigs on the feed containing different types of used fat.
Material and methods. Meat was obtained from pigs fed in 4 experimental groups, from which groups A and B were given the mixture of rapeseed oil and linseed oil in the ratio of 1:2.5 or 2.3:1:0.2 (lard) as the source of fat. In group C, animals were given the mixture of rapeseed oil (1 part), fi sh oil (cod-liver oil; 2 parts) and lard (0.5 part), whereas group D obtained the mixture of linseed oil in the same ratio as in group B (2.5 parts), but combined with cod-liver oil (1 part). Meat collected for the research was evaluated and underwent chemical analyses in order to determine its nutritional value. The contents of moisture, protein, fat and ash were determined according to the AOAC methods. The carbohydrate content in various samples was determined by subtracting the sum of moisture, protein, ash and fat content from 100. Energy value (EV) was calculated using Atwater factors. The fatty acids content were analysed in homogenized samples using Folch method. Methyl esters of fatty acids were separated by gas chromatography on GC Trace Ultra THERMO company equipped with a RT 2560 RESTEC capillary column (100 m × 0.25 mm × 0.2 μm) with helium as a carrier gas.
Result. The modifi cation of the source of fat in pigs feed did not infl uence the content of protein and total minerals (ash), whereas it signifi cantly infl uenced the content of fat and moisture. It has been stated that the use of different fat type in pigs feed, contributed to receiving the meat with modifi ed profi le of fatty acids. Higher fatty acids of the n-3 was observed in groups B and D (treated with the mixture of oils with a predominance of linseed oil). The fat from the meat of these groups contain less of n-6 and n-9 fatty acid, which
improved the quality indicator of the fat expressed as the ratio of n-6 / n-3. Meat obtained from animals of the groups contained signifi cantly less MUFA, and comparable content UFA and SFA. The meat from all experimental groups the ratio of polyunsaturated fatty acids (PUFA), saturated fatty acids (SFA) remained at a similar level and was 0.5:0.6.
Conclusions. The modifi cation of the source of fat in pigs feed did not infl uence the content of protein and total minerals (ash), whereas it signifi cantly infl uenced the content of fat and moisture. A different source of fat in pigs feed did not infl uence the content of fat, saturated fatty acids (SFA) and UFA (unsaturated fatty acids) in fat, whereas it signifi cantly infl uenced the participation of  particular fatty acids belonging to monounsaturated (MUFA) and n-3 and n-6 groups.

Effects of complementary and excess diet supplementation with selected minerals on their metabolism and distribution in the body: a model study

Introduction. The study was aimed at determining, on an animal model, effects of supplementing a diet, modifi ed by substituting whole wheat and corn grains with white fl our and sucrose, with calcium, magnesium, zinc, and chromium on metabolism of the minerals and their distribution in the body.
Material and methods. The study involved 4 groups of Wistar rat females (n = 11) fed: a standard feed (group I) containing, i.a., whole wheat and corn grains; modifi ed feed (84% and 50% of whole wheat and corn grains, respectively, in the standard feed substituted with Type 500 wheat fl our and sucrose, respectively) (group II); modifi ed feed with complementary supplementation (elimination of Ca, Mg, Zn, and Cr defi ciencies resulting from diet modifi cation) (group III); and modifi ed feed with excess supplementation (the same minerals applied in excess, i.e., amounts from 0.5 to 3 times higher than the defi ciencies produced by diet modifi cation) (group IV). The replacement of whole grains with white fl our and sucrose, as well as the mineral  supplementation could, to some extent, imitate the contemporary eating habits and supplementation applied in food technology. The excess supplementation is, on the other hand, typical of current behaviours of various social groups.
Results. Both types of supplementation resulted in a signifi cant increase in the perivisceral adipose tissue content, but did not affect the fat tissue content in muscles. The supplementation applied did not change the content of calcium, magnesium, and zinc in muscles, nor did it signifi cantly change calcium and magnesium excretion with urine. However, changes in the ALP activity and calcitonin concentration did not suggest the deposition of the minerals in bones.
Conclusions. Analysis of the results allowed to conclude that: 1) except for chromium, contents of the selected minerals in the tissues examined and urea, as well as concentrations of calcitonin and alkaline phosphatase (ALP) activities did not point to any signifi cant effect of the supplementation applied on the body contents of those minerals; 2) effects observed as the accumulation of perivisceral, epicardial and intramuscular adipose tissue, as well as increased body weight increments could have been related to disturbed proportions of the minerals supplemented, their synergy and antagonism and, consequently, a potential generation of secondary defi ciencies and excesses which could signifi cantly affect individual metabolic pathways; 3) the intensity of changes observed was generally higher in the females receiving complementary supplementation, although their uptake of minerals studied was similar to that shown by the females kept on the standard diet.