ACTA Scientiarum Polonorum - Technologia Alimentaria News en (c) Wydawnictwo Uniwersytetu przyrodniczego w Poznaniu Effect of antioxidants on polyunsaturated fatty acids – review

This paper aims to review the available literature data and provide an overview regarding the efficiency of antioxidants to prevent peroxidation of polyunsaturated fatty acids. Lipid peroxidation is a serious problem that often leads to a loss of shelf-life, reduced consumer acceptability, poorer functionality, lower nutritional value, and poorer safety. It represents an oxidative degradation of polyunsaturated fatty acids incorporated in cell membrane lipids or in lipoproteins, but also in vegetables and food oils rich in PUFA n-3. It is a complex process that leads to the production of numerous highly reactive metabolites with consequences for food preservation and for the development of various diseases. The targets of lipid oxidation are polyunsaturated fatty acids. Lipid peroxidation can proceed by means of two different reactions that lead to the formation of hydroperoxides as primary products. Hydroperoxides decompose rapidly to give many secondary products, such as lipid free radicals, which contribute to increased oxidation of other molecules, such as proteins, nu- cleic acids and other lipids. Lipid peroxidation is a major problem for the food industry, as well as for human health, since it is associated with many diseases. The use of antioxidants reduces oxidative damage.

New model for colour kinetics of plum under infrared vacuum condition and microwave drying

Background. Quality of dried foods is affected by the drying method and physiochemical changes in tissue. The drying method affects properties such as colour. The colour of processed food is one of the most impor- tant quality indices and plays a determinant role in consumer acceptability of food materials and the process- ing method. The colour of food materials can be used as an indirect factor to determine changes in quality, since it is simpler and faster than chemical methods.
Material and methods. The study focused on the kinetics of colour changes of plum slices, under infrared vacuum and microwave conditions. Drying the samples was implemented at the absolute pressures of 20 and 60 kPa, drying temperatures of 50 and 60°C and microwave power of 90, 270, 450 and 630 W. Colour changes were quantified by the tri-stimulus L* (whiteness/darkness), a* (redness/greenness) and b* (yellow- ness/blueness) model, which is an international standard for color measurement developed by the Commis- sion Internationale d’Eclairage (CIE). These values were also used to calculate total colour change (∆E), chroma, hue angle, and browning index (BI). A new model was used for mathematical modelling of colour change kinetics.
Results. The drying process changed the colour parameters of L*, a*, and b*, causing a colour shift toward the darker region. The values of L* and hue angle decreased, whereas the values of a*, b*, ∆E, chroma and browning index increased during exposure to infrared vacuum conditions and microwave drying. Comparing the results obtained using the new model with two conventional models of zero-order and first-order kinet- ics indicated that the new model presented more compatibility with the data of colour kinetics for all colour parameters and drying conditions.
Conclusion. All kinetic changes in colour parameters can be explained by the new model presented in this study. The hybrid drying system included infrared vacuum conditions and microwave power for initial slow drying of plum slices and provided the desired results for colour change.

Influence of freezing and storing cherry fruit on its nutritional value

Background. Cherries are a valuable dietary raw material and possess medicinal properties. Considering the nutritional, medical and vitamin value of cherry fruits, the purpose of this research was to produce a scientific justification for preserving the quality of cherry fruits using different freezing methods.
Material and methods. To do this, cherry fruits from the Lotovka (Cerasus vulgaris) variety were frozen in various ways: packed in polyethylene bags (control); previously suspended in a 20% sugar solution and pack- ing frozen cherry in polyethylene bags; suspended in a 20% sugar solution with the addition of 4% ascorutin and frozen followed by pre-packaging in polyethylene bags; cherry fruits were frozen in a 20% sugar solution in plastic cups of 0.25 cm3; they were also frozen in a 20% sugar solution with the addition of 4% ascorutin in plastic cups. The frozen products were stored at a temperature not higher than –18°C for up to 6 months.
Result. Studies have shown the appropriateness of freezing cherry fruits, particularly in a 20% sugar solution with the addition of 4% ascorutin. The advantages of these fruits are in ascorbic acid preservation in 1.5 times and reduction of tanning and coloring substances only by 27%, soluble solids to 7%, sugars – 4%, acids – 12%, in tasting evaluation of 5 points.
Conclusions. Frozen cherry fruits in a 20% sugar solution with the addition of 4% ascorutin can be used in dietary nutrition for patients with cardiovascular diseases.

Fermentation optimization of goat milk with Lactobacillus acidophilus and Bifidobacterium bifidum by Box-Behnken design

Background. Goat milk is only limited to the processing of goat milk powder and liquid milk, the products are mainly about milk powder and a few of them are made as milk tablet. Therefore, the study of probiotic goat milk will have great significance in the full use of goats and the development of the goat milk industry in China.
Methods. The effect of fermentation temperature (35°C, 37°C, 39°C), strain ratio (1:1:1, 2:1:1, 3:1:1) and in- oculum size (4%, 5%, 6%) on viable counts of L. acidophilus and B. bifidum, total bacteria and sensory value during fermentation process of L. acidophilus and B. bifidum goat yogurt (AB-goat yogurt) was investigated.
Results. The optimum fermentation conditions for AB-goat yogurt were: fermentation temperature 38°C, the strain ratio 2:1:1, inoculum size 6%. Under the optimum conditions, the viable counts of B. bifidum, L. aci- dophilus, total bacteria and sensory value reached (4.30 ±0.11)×107  cfu/mL, (1.39 ±0.09)×108  cfu/mL, (1.82±0.06)×109  cfu/mL and 7.90 ±0.14, respectively.
Conclusion. The fermentation temperature, the strain ratio and inoculum size had a significant effect on the fermentation of AB-goat yogurt and these results are beneficial for developing AB-goat yogurt.

Sensory qualities of pastry products enriched with dietary fiber and polyphenolic substances

Background. Growing consumer demand for products with pro-health properties is forcing food manufactur- ers to introduce new food items onto the market, which will not only possess such health-enhancing proper- ties but will also compete on the grounds of sensory attributes – taste, flavour, texture etc.
Material and methods. The aim was to evaluate these sensory attributes of pastry products enhanced with biologically active compounds, such as inulin, buckwheat hull and buckwheat flour. For decreasing the ener- gy value of the products tested (crispy cookies, muesli cookies, waffles and pancakes) some ingredients were replaced: vegetable butter or oil by inulin and wheat flour by roasted buckwheat flour and thermally processed buckwheat hull. The substances mentioned are rich sources of soluble and insoluble buckwheat fiber, and also polyphenolic substances. Dry chokeberry and mulberry leaf extract were added as a rich source of flavonoids and 1-deoxynorijimycin, respectively. These substances are recommended for people with obesity. The pro- cessing was carried out at 175°C for 15 minutes using a convection oven (Rational Combi-Steamer CCC).
Results. Pastry products with buckwheat flour, buckwheat hulls, mulberry extract, chokeberry and inulin had a lower food energy, a higher dietary fiber content and scored high on customer desirability.
Conclusions. Pastry products which contain ingredients carrying biologically active substances are not only at- tractive from the sensory point of view, but also low in calories, and are thus recommendable for obesity people.

Evaluation the effect of gamma irradiation on microbial, chemical and sensorial properties of peanut (Arachis hypogaea l.) seeds

Background. The aim of the present study was to evaluate the possibility to apply gamma radiation treatment for decontaminating and assuring the quality of peanut seeds.
Material and methods. The radiation processing was carried out at dose levels of 3, 6 and 9 kGy. The ir- radiated and non-irradiated (control) samples were stored at room temperature for 12 months, and analyzed for microbial load, proximate composition, sensorial acceptance and chemical properties.
Results. The results indicated that gamma irradiation treatment significantly (p < 0.05) reduced microbial load and enhanced the safety of the irradiated samples. The irradiated samples were also acceptable sensori- cally. The total acidity and total volatile nitrogen (TVBN) contents increased with the increase of radiation dose. Furthermore, in general, no substantial change in proximate constituents was observed amongst the samples. No significant (p > 0.05) differences in the taste, flavor, color and texture score were observed among treatments (0, 3, 6 and 9 kGy).
Conclusion. Irradiation protected again bacterial and fungal growth and retained the nutritional components of samples during long-term storage.


Background. The aim of this study was to determine the best extraction conditions for total phenolic con- tent (TPC) and antioxidant capacity (AC) of Polygonum multiflorum Thunb. root using microwave-assisted extraction (MAE).
Material and methods. The raw material used was Polygonum multiflorum Thunb. root powder. Five fac- tors such as solvent type, solvent concentrations, solvent/material ratio, extraction time and microwave power were studied; TPC and AC values were determined by the Folin-Ciocalteu method and DPPH free radical scavenging activity measurement, respectively. In addition, studies involved assaying the HPLC test of extracts and SEM of samples.
Results. Optimal results pointed to acetone as the solvent, acetone concentration of 60%, solvent/material ratio of 40/1 (v/w), extraction time of 5 mins and microwave power of 127 W. TPC and AC obtained were approximates 44.3 ±0.13 mg GAE/g DW and 341.26 ±1.54 μmol TE/g DW, respectively. The effect of mi- crowaving on the cell destruction of Polygonum multiflorum Thunb. root was observed by scanning electron microscopy (SEM). Some phenolic compounds were determined by the HPLC method, for instance, gallic acid, catechin and resveratrol.
Conclusion. These factors significantly affected TPC and AC. We can use acetone as a solvent with micro- wave-assisted extraction to achieve the best result.

Evolution of free amino acids, biogenic amines and n-nitrosoamines throughout ageing in organic fermented beef

Background. In recent years, interest in uncured meat products has grown and studies were carried out on the use of substances which could replace nitrites, such as acid whey. In spite of this problem in fermented meat products, there is no information regarding the effects of prolonged ageing on the formation of chemi- cal (nitrosoamines, biogenic amines, secondary lipid oxidation products) and microbiological (L. monocy- togenes, S. aureus, OLD) toxicants in fermented beef marinated with acid whey. The aim of this study was to determine the selected pathogenic bacteria, biogenic amines, N-nitrosamines contents in fermented beef subjected to extended ageing.
Material and methods. In this study, selected pathogenic bacteria, N-nitrosamines, biogenic amines, amino acids, TBARS values changes during the ageing of fermented beef marinated with acid whey were analyzed in 0-, 2- and 36-month-old samples.
Results. The pH values of fermented beef aged for 2 months (5.68, 5.49 and 5.68 respectively) were sig- nificantly lower (p < 0.05) than those obtained after the end of the manufacturing ripening period (5.96, 5.97 and 5.74 respectively), which confirmed the effectiveness of the fermentation process of acidification on beef. The high Lactic Acid Bacteria content (5.64–6.30 log cfu/g) confirmed this finding. Histamine was not detected in either of the products. The highest concentration of total biogenic amine (i.e. 1159.0 mg/kg) was found in fermented beef marinated with acid whey, whereas a total of only 209.8 mg/kg, was observed in control beef with nitrate and nitrite. N-nitrosamines were not detected in any of the ageing beef samples.
Conclusion. In this study, marinating beef in acid whey did not inhibit the production of biogenic amines in the samples analyzed. The high concentration of FAAs, the potential precursor of BA, could lead to intense peptidase activity. The results obtained indicate that biogenic amines are not direct precursors for nitrosa- mines formation in fermented beef. The LAB strain from acid whey reduced the pH value during the first stages of ageing and ensured the microbiological safety of the product not only in the first stage of fermenta- tion but also at the end of ageing (36 months).

The role of intestinal microbiota in the pathogenesis of metabolic diseases

The incidence of metabolic diseases is increasing rapidly all over the world. This situation has led researchers to attempt to explain the pathomechanisms of these disorders and to develop specific recommendations for the prevention and treatment of diseases such as obesity, type-2 diabetes, and atherosclerosis. Recent studies show clear evidence of the role of human intestinal microbiota in health and in predispositions to diseases. Gut microbiota affect a number of complex metabolic reactions, significantly altering the functioning of the human body. Numerous experiments have shown the key role played by the formation process of the intesti- nal ecosystem in the early stages of human life for programming its metabolic health. The following article is a compilation of the literature available on the formation of the complex intestinal ecosystem and its impact on the incidence of diseases such as obesity, type-2 diabetes, and atherosclerosis.

The effects of a low-calorie diet or an isocaloric diet combined with metformin on sex hormones In obese women of child-bearing age

Background. The influence of weight loss treatment on sex hormones profile has been studied mainly in women with polycystic ovary syndrome (PCOS), but in obese premenopausal women without PCOS it still remains unclear. The aim of the study was to evaluate the effect of two approaches to obesity treatment on the serum level of sex hormones in obese women of child-bearing age without PCOS.
Material and methods. 77 obese Caucasian women (aged 31.2 ±8.3 years) were randomized into two groups: 39 women received a low-calorie diet (LC) and 38 received an isocaloric diet plus metformin (IM), for 12 weeks. Anthropometric parameters, body composition and serum concentrations of estradiol (E2), testosterone (T), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and dehydroepiandrosterone (DHEA-S) sulfate were evaluated at baseline and after the study.
Results. Reductions in body weight, body mass index (BMI), waist and body fat content with an increase  in lean body percent were significant and comparable between the LC and IM group after the trial. The con- centrations of serum FSH, LH, E2, DHEA and T did not change in either group after treatment. A tendency towards an increase in the E2 concentration in both groups and a decrease in the T level in the LC group  was observed. The correlations between a change in BMI, fat content, waist-hip ratio and a change in T were documented in the LC group.
Conclusion. A 12-week low-calorie diet and an isocaloric diet combined with metformin produced comparable and significant weight loss with improvements in body composition. Both interventions did not significantly affect FSH, LH and DHEA sulfate serum concentrations, only a trend towards an E2 increase and a T decrease was observed, stronger in LC group. The significant correlations shown between the changes in anthropometric and body composition parameters and T serum levels in women treated with a low-calorie diet alone show the beneficial effect of a lifestyle intervention on the sex hormone in obese premenopausal women.

Phenylketonuria is not a risk factor for changes of inflammation status as assessed by interleukin 6 and interleukin 8 concentrations

Background. High oxidative stress and a reduced potential for free radical scavenging in phenylketonuria (PKU) patients, a phenomenon confirmed in a few studies, may lead to systemic chronic inflammation. The aim of this study was to compare the inflammation status, as assessed by interleukin 6 and interleukin 8 con- centrations, in patients with PKU and in healthy controls.
Material and methods. Twenty patients with classical PKU, aged 18–34 years and under dietary control, were enrolled in the study. The control group comprised of 20 healthy subjects matched for age and sex. Interleukin 6 and 8 levels were measured by enzyme-linked immunosorbent assay (ELISA) kits in all study participants.
Results. IL-6 concentrations in the study group ranged from 0.74 pg/ml to 1.34 pg/ml. No significant dif- ferences were found between IL-6 concentration between the study group and the control group (p = 0.989). IL-8 concentrations ranged from 17.56 pg/ml to 20.87 pg/ml. The obtained results of IL-8 levels did not differ significantly between the study group and control group (p = 0.192). No significant correlation was observed between Phe blood levels and IL-6 or IL-8 concentrations in the study group (ρ respectively: –0.225, 0.177). In a multivariate analysis, neither IL-6 nor IL-8 concentrations were correlated with sex, age, BMI and Phe levels.
Conclusions. Phenylketonuria is not a risk factor for changes of inflammation status as assessed by IL-6 and IL-8 concentrations.