Volume 25 (2021): Issue 2 (December 2021)

Since ancient times, sheep`s milk cheeses have been a part of a human diet. Currently, their consumption is of great interest due to its nutritional and health values. The aim of the article was to review the chemical composition of sheep’s milk cheeses and its main bioactive ingredients in the context of nutritional and health values. Sheep’s milk cheeses are rich in functionally and physiologically active compounds such as: vitamins, minerals, fatty acids, terpenes, sialic acid, orotic acid and L-carnitine, which are largely originate from milk. Fermentation and maturation process additionally enrich them in other bioactive substances as: bioactive peptides, γ-aminobutyric acid (GABA) or biogenic amines. Studies show that sheep’s milk cheese consumption may be helpful in the prevention of civilization diseases, i.e. hypertension, obesity or cancer. However, due to the presence of biogenic amines, people with metabolic disorders should be careful of their intake.

The purpose of this study was to determine phenolic profile and antioxidant activity of the selected edible flowers grown in Poland. A significant variation was observed in the both antioxidant activity and total phenolic content. Marigold flowers were characterized by the highest total phenolic content (89.22 mg GEA/g dry weight). In turn, begonia flowers exhibited the highest total flavonoids and phenolic acids content (21.96 mg QE/g dry weight, and 8.60 mg CAE/g dry weight, respectively). Taking into account the type of flowers, begonia and marigold flowers were the richest in phenolic acids. Caffeic and p-coumaric acids were the most frequent ones in the edible flowers grown in Poland. While gallic and p-coumaric acids were the prevalent ones in terms of their content. The begonia and marigold flowers contained quercetin and kaempferol, while hesperetin and naringenin were present in the chives flowers. The marigold flowers were characterized by a particularly high content of quercetin, and also exhibited the highest total antioxidant activity. The methanolic extracts of marigold and begonia flowers were characterized by the highest antioxidant activity, reducing activity, as well as the highest ability to neutralize free radicals.

This work aimed to enumerate the Bacillus cereus sensu lato from infant’s flour sampled at Béchar city and evaluate its resistance to different heating conditions during meal preparation patterns at home. Our findings revealed a prevalence of 74% with 2.4 to 3.9 CFU/g in the analyzed samples. Regarding the heat resistance at 90 °C to 98 °C, our results showed heat resistance variability which depends on the isolate, for example, D_{90 °C} and z_{T °C} values varied from 3.24 to 5.52 min and 11.56 to 89.74 °C respectively. Then, the decimal reduction (n) was calculated at all preparation temperatures (50, 60, 70, 80, 90 and 100 °C). Low “n” was observed with the preparation at T≤50 °C as recommended by the fabricant. However, at the other temperatures, high “n” was observed at 100°C with median and 95^th values of 2.22 and 12.36 respectively. Therefore, bacterial concentrations (99^th) were estimated at 0.124 log CFU/g for 100 °C. These concentrations could be increased with bacterial growth during meal storage and then achieve critical concentrations. Thus, the results of this work highlight the interest to establish a risk assessment for babies and to improve the production, preparation, and storage conditions of the infant’s flour.

Milk provides some beneficial fatty acids which in dairy processing are subjected to pasteurization and fermentation. With the aim to assess such changes, aliquot parts of milk from 12 buffaloes were pooled and processed to germinated yoghurt and brined cheese, and to non-germinated curd – the respective samples of raw and dairy material subjected to lipid analysis. The results show that in cheese positive and negative changes are generally balanced, rumenic acid decreasing and other CLAs altered but not total CLA and PUFA; omega ratio and atherogenicity index worsened to little extent, due to adverse change in n-3, myristic and lauric acid. In yoghurt and curd CLA dramatically decreased, excluding rumenic acid; but vaccenic acid increased, though total trans isomers decreased; the worsened n-6/n-3 ratio and atherogenicity index is mostly because of the adverse effect on PUFAn-3 but also on myristic and lauric acid. In all products SFA and MUFA did not change, including palmitic, stearic, and oleic acid. It can be concluded that the decrease of CLA in yoghurt and curd is partially compensated by the increase in the vaccenic acid, while cheese making altered individual isomers but not groups of beneficial acids.

The study assesses impact of malting process duration on malting losses and quality of malts obtained from three varieties of winter wheat, i.e., Elixer, Rockefeller and Gimantis. The findings show that increased duration of the malting process (from 4 to 7 days) corresponded to greater total weight loss, with the most significant differences observed between 5-day and 6-day wheat malts. The qualitative analysis of the malts was carried out in accordance with EBC methodology. The assessments showed that the 5-day long malting process applied to the relevant wheat varieties resulted in production of high-quality malt with optimum malting losses observed in the case of Elixer and Rockefeller varieties. Slightly higher malting losses were identified in the case of Gimantis, and the malt obtained from this variety had very high contents of soluble protein (on average 5.34% d.m.) and Kolbach Index (average of 50.49%), which reflects high proteolytic activity during the grain malting process and a need to modify the malting process for this variety.

This study is designed to evaluate the effect of wheat flour substitution with Clerodendrum volubile at different level (1, 3, 5 and 10%) on antioxidant, proximate, mineral and sensory acceptability of wheat bread. The wheat flour was substituted with CVLP at different level (1, 3, 5, and 10%) in the baking of the wheat bread. The inclusion of CVLP led to significant (p < 0.05) and dose dependent increases in the polyphenol contents and antioxidant properties of the CVLP-substituted bread. Also, there were significant (p < 0.05) increments in the crude fibre, crude ash and many mineral elements of the CVLP-substituted breads. Antinutrient (tannins and oxalate) contents of the wheat bread substituted with 10% CVLP were significantly higher (p < 0.05) than the wheat bread. Consumer acceptability of the substituted breads showed that wheat bread with 5% CVLP inclusion has the best acceptance. Therefore, 5% CVLP inclusion is recommended as a suitable level in the bread making.

The aim of the study was to examine the influence of meteorological conditions observed during the process of traditional smoking on polycyclic aromatic hydrocarbon content in traditional Polish pork ham. The material of the study comprised traditional Polish pork ham, one of the most frequently purchased and consumed meat products in Poland. The analysed ham was smoked with the traditional method using beech chips and pieces. Smoking time was four hours. During laboratory research the basic chemical composition of the product was examined. Using the HPLC method, the level of 15 selected Polycyclic Aromatic Hydrocarbons (PAHs). The obtained results show that the level of selected polycyclic aromatic hydrocarbons in the examined material depended on atmospheric pressure and relative air humidity. Atmospheric pressure significantly influenced the content of benzo(b)fluoranthene, benzo(a)anthracene and indeno(c,d)pyrene. Relative humidity impacted the absorption level of 5-methylchrysene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene, benzo(j)fluoranthene and indeno(c,d)pyrene. An influence of air temperature during the smoking process on PAHs content in the product was not observed. The results indicate that traditional smoking should be conducted under conditions of high relative humidity – ideally above 75%, and high atmospheric pressure – above 1000 hPa.

This study uses artificial neural network (ANN) to predict the thermo-physical properties of deep-fat frying plantain chips (ipekere). The frying was conducted with temperature and time ranged of 150 to 190 °C and 2 to 4 minutes using factorial design. The result revealed that specific heat was most influenced by temperature and time with the value 2.002 kJ/kg°C at 150 °C and 2.5 minutes. The density ranged from 0.997 – 1.005 kg/m³ while thermal diffusivity and conductivity were least affected with 0.192 x 10⁻⁶ m²/s and 0.332 W/m°C respectively at 190 °C and 4 minutes. The ANN architecture was developed using Levenberg–Marquardt (TRAINLM) and Feed-forward back propagation algorithm. The experimentation based on the ANN model produced a desirable prediction of the thermo-physical properties through the application of diverse amount of neutrons in the hidden layer. The predictive experimentation of the computational model with R² ≥ 0.7901 and MSE ≤ 0.1125 does not only show the validity in anticipating the thermo-physical properties, it also indicates the capability of the model to identify a relevant association between frying time, frying temperatures and thermo-physical properties. Hence, to avoid a time consuming and expensive experimental tests, the developed model in this study is efficient in prediction of the thermo-physical properties of deep-fat frying plantain chips.

Cell envelope proteases (CEPs) can break down milk protein into peptides with different functions, which are of great benefit to human health. Therefore, the high-yield CEPs of Lactobacillus plantarum have the potential to produce functional dairy products. In previous experiments, we found that Na₂HPO₄, inulin, casein peptone and leucine have significant effects on CEP production by Lactobacillus plantarum LP69. So we proceeded to optimize the composition of the CEP-producing culture medium of L. plantarum through Box-Behnken design and response surface methodology. The protease activity, protein content and specific activity of CEPs produced by L. plantarum by inulin (0.2, 0.3, 0.4 %), casein peptone (0.4, 0.6, 0.8 %), Na₂HPO₄ (0.50, 0.52, 0.54 %) and leucine (14, 16, 18 mg/L) were evaluated. The optimal ratio of medium is 0.4 % inulin, 0.66 % casein peptone, 0.5 % Na₂HPO₄ and 14.04 mg/L Leucine. The final enzyme activity reached (24.46±0.81) U/mL, and the specific activity reached (1.41±0.46) U/mg.

Lactose intolerance is an important factor restricting the consumption of dairy products. Lactase is used to hydrolyze lactose in milk while generating galactooligosaccharides (GOS), thereby reducing the incidence of lactose intolerance. We used cow milk as raw materials, and selected enzyme preparations with high lactose hydrolysis rate and strong GOS generation ability from 14 commercially available lactase enzymes. The lactose hydrolysis rate is 5.85%-81.38%, and the GOS content is 0.03 g/L- 13.10 g/L. The mixing experiment design determined the two lactase enzymes (E10 and E11) ratio and the optimal enzymatic hydrolysis process of low-lactose prebiotic milk: compound lactases (E10:E11=0.756:0.244) addition 0.11%, 55℃for 5h, lactose hydrolysis rate and GOS content were 98.02% and 19.69g/L, respectively, and the remaining lactose content was about 0.97 g/L.

The aim of this research was to demonstrate the effect of the ozonation process (exposure to ozone in gaseous form and rinsing in water saturated with ozone) on selected apple parameters. The scope of the study included: conducting the ozonation process under controlled conditions at a concentration of 1 ppm and exposure times of 1, 5 and 10 min (ozone in gaseous form) and 10, 15 and 30 min (ozonated water), respectively; polyphenols research; determining antiradical activity using ABTS radicals; and determining the influence of the applied method on the volatiles that give rise to odor chemicals (fragrance and aroma). In both cases, measurements were taken 24 hours after the ozonation process. Both exposure to ozone in gaseous form and washing in ozonated water did not adversely affect the appearance of the fruit. The rinsing process in ozonated water did not significantly affect the composition of the compounds responsible for the fruit’s odor. The proposed washing conditions affected the biochemical balance of the fruit. Differences in polyphenol content and antioxidant potential were noted. The mean content of polyphenols expressed as gallic acid equivalent in the control sample was determined to be 15.22 mg/100 g. In comparing the content of polyphenols with the control sample, insignificant changes in their content were noted, except for the sample with the longest ozonation. In the case of fruit washed within 30 minutes, a significant increase by 53% in antioxidant potential was noted. α- Farnesene was identified as the main component established by headspace solid-phase microextraction (HS-SPME) procedure. The proposed ozonation conditions made it possible to keep the volatile compounds influencing the sensory properties of apples unchanged.

Fruit beverages are the most consumed refreshing products worldwide. The quality of these drinks is not only influenced by the initial composition of the product but also by conditions and duration of storage. The purpose of the present investigation was to evaluate the incidence of two conservation parameters (temperature and time) on some bioactive compounds (phenolic, flavonoid, and carotenoid contents) and antioxidant capacity, measured by free radical scavenging activity (RSA) and ferric reducing power (FRP), on orange beverage during storage. The industrial drinking product freshly procured were subjected to storage under variable temperatures (5, 25, 35, and 45 °C) then analyses of bioactive compounds contents and antioxidant activity were performed periodically (0, 10, 20, and 30 days). The results showed that the initial orange beverage was endowed with interesting phenolic compound contents and considerable antioxidant potential. In the exception of 5 °C, which provided steady antioxidant parameters, all other temperatures induced decreases of analyzed phytochemicals and antioxidant activities proportionally with raising of storage temperature. The duration of storage for the temperatures 25, 35, and 45 °C also affected negatively antioxidant parameters in a proportional manner to time. The orange beverage was an interesting natural source of bioactive compounds but the duration of storage in relation to temperature must be chosen properly.

Lactobacillus delbrueckii subsp. bulgaricus is widely used in yogurt as a starter. The freeze-drying process may cause bacteria death. In the present work, the effect of three solutes (NaCl, sorbitol, and sodium glutamate) in MRS on viability of L.bulgaricus during freeze-drying was investigated. The optimal combination of adequate solutes was chosen by Box-Behnken Design. The survival rate and viable counts in freeze-dried powder, as well as the viable counts in broth, were used as responses. The results revealed that the optimum combination of solutes in MRS broth were 0.50% NaCl, 0.19% sorbitol, and 0.06% sodium glutamate. Under these optimal conditions, the survival rate was 53.2±0.14%, the viable counts in freeze-dried powder was 8.51±0.23×10¹⁰ CFU/g, and the viable counts in broth was 6.05±0.19 ×10⁸ CFU/mL, which were increased by 17.18%, 15.94%, and 17.31%, respectively, compared to the control. This research demonstrated the possibility of viability improvement of L.bulgaricus, which may provide a feasible reference for industrial development.