ACTA Scientiarum Polonorum - Technologia Alimentaria News en (c) Wydawnictwo Uniwersytetu przyrodniczego w Poznaniu Methods to increase the rate of mass transfer during osmotic dehydration of foods

Traditional methods of food preservation such as freezing, freeze drying (lyophilization), vacuum drying, convection drying are often supplemented by new technologies that enable obtaining of high quality products. Osmotic dehydration is more and more often used during processing of fruits and vegetables. This method allows maintaining good organoleptic and functional properties in the finished product. Obtaining the desired degree of dehydration or saturation of the material with an osmoactive substance often requires  elongation of time or use of high temperatures. In recent years much attention was devoted to techniques aimed at increasing the mass transfer between the dehydrated material and the hypertonic solution. The work reviews the literature focused on methods of streamlining the process of osmotic dehydration which include the use of: ultrasound, high hydrostatic pressure, vacuum osmotic dehydration and pulsed electric field.

Screening of probiotic goat milk tablets using Plackett-Burman design

Background. Probiotics defi ned as additional microorganisms were added to goat milk powder, which not only improves the intestinal fl ora balance but also promotes human and animal health. The objectives of this study were to improve and guarantee high probiotics viable count and accordance with consumer’s acceptance.
Material and methods. The reading selected the number of colony between 30 and 300, then calculated the viable count per gram of goat milk tablet (cfu/g). The items of sensory evaluation included: appearance, fl avour, colour, texture and taste. The score test was composed of 5 trained assessors, scored combination of different formulations (full marks of 100 points) and recorded the results.
Results. Analysis of the results showed that sucrose, inulin and mannitol were selected as the main effective parameters on both viable count and sensory evaluation. Furthermore optimization of the formulation of probiotic goat milk tablets was to maximise the probiotics viable count to achieve 9.5·108 cfu/g and its scores of sensory evaluation to get 94 points.
Discussion. Future probiotics products will be combined with a variety of probiotics, which can display their respective advantages and characteristics. Thus the products will not only be in accordance with the requirements of human health and trend of social development, but also will quickly become a favorite among consumers.

Health stimulating properties of the most popular soft cheese in Egypt Kariesh made using skimmed milk UF-retentate and probiotics

Background. Soft skimmed-milk cheese Kariesh is the most popular soft cheese in Egypt. In the past, Karish cheese was traditionally produced by the random fermentation of milk speared its cream layer by the gravity force. Recently, its production has been carried out by several manufacturing procedures using, ultrafi ltration (UF) – skimmed milk retentate, certain bacterial cultures, enzymatic coagulation, etc. Therefore, the biological and nutritional evaluations are required. The present study was conducted to evaluate the properties of such cheese coagulated using different procedures involving probiotic strains with emphasis on some chemical and biological attributes.
Material and methods. Kariesh cheeses were manufactured without whey drainage from UF cow’s skimmed milk concentrate coagulated either by 3% yoghurt bacterial starter culture (YC), 3% probiotic starter culture (ABT type) or 2.5% glucono delta lactone (GDL) added whether separately or incorporated with rennet (0.05ml/kg) to achieve the acidic-enzymatic coagulation in comparison with those made conventionally using unconcentrated milk coagulated either by 2% of YC or ABT added whether separately or incorporated with rennet (0.25 ml/kg). Due to the fact that whey is naturally needed to drain in the conventional (C) procedure, the use of GDL as coagulant was eliminated.
Results. The obtained results indicated that the application of UF-technique in Kariesh cheese industry was associated with signifi cant increments in the values of protein, ash and pH. Moreover, the electrophoretical patterns of UF-Kariesh cheese obtained with the incorporation between YC, ABT or GDL and rennet were distinguished with the presence of the band of glycomacropeptide, which is normally lost in the whey through the C-procedure. Furthermore, the food intake (FI), body weight gain (BWG), food efficiency ratio (FER),triglycerides (TG), total cholesterol (TC), high density lipoproteins (HDL), total, as well as ionized Ca of blood and the count of lactic acid bacteria of feces of rats were signifi cantly heightened, while low density lipoprotein (LDL) level was lowered as they fed on UF-cheeses, especially when coagulated using ABT, those caused the strongest persistence against the rat colon tumor, which was induced by the injection with 1,2 di-methyl hydrazine. The use of ABT led to raise the dry matter (DM) and ash of Kariesh cheese. Also, the FI, BWG, FER, TG, total, as well as ionized Ca of blood and the count of lactic acid bacteria of feces of rats were signifi cantly increased, while TC, HDL and LDL of blood, as well as coliform count of feces of rats were signifi cantly declined. The incorporation of enzymatic with acidic coagulation in Kariesh cheese manufacture increased signifi cantly the values of ash and pH. However, the cheese fi gures of DM, protein and titratable acidity were decreased. Also, the values of FI, BWG, FER, TC, HDL, LDL and feces LAB of rats were lowered. Whilst, the values of TG, total as well as ionized Ca and feces coliform of rats were increased.

New-vista in fi nding antioxidant and anti-infl ammatory property of crude protein extract from Sauropus androgynus leaf

Aim. This study describes antioxidant and anti-infl ammatory properties of Sauropus androgynus leaf dialysed protein extract. Free radicals are implicated for many diseases including diabetes mellitus, arthritis, cancer, ageing etc. In the treatment of these diseases, antioxidant therapy has gained utmost importance. The main objective of the present study was to reveal the antioxidant and anti-infl ammatory potentiality from S. androgynus leaf dialysed protein extract.
Material and methods. The antioxidant and anti-infl ammatory properties of S. androgynus studied using different models viz. hydroxyl radical scavenging, DPPH radical scavenging, reducing power assay, superoxide radical scavenging activity by alkaline DMSO and phosphomolybdenum antioxidant assays and in vitro antiinfl ammatory activity by inhibition of protein denaturation, membrane stabilisation test models carried out.
Results. Antioxidant activity was estimated in dose dependent manner showed hydroxyl radical (55.62%), DPPH (50%), reducing power (0.286 Abs), alkaline DMSO (72.51%) and phosphomolybdenum (0.198 Abs) activity high at 50 μg/ml concentration compared to standard curcumin (62.31%), curcumin (56.61%), tannic acid (0.54 Abs), curcumin (75.38%) and vitamin E (0.15 Abs) respectively. In-vitro anti-infl ammatory activity by hypotonic induced model showed maximum protection (74.17%) compared to standard Acetylsalcylic acid (86.88%) at 100 μg/ml concentration and also in protein denaturation model protected protein denaturation maximum (83.60%) compared to standard Diclofenac (86.82%) at 100 μg/ml concentration respectively.
Conclusion. The antioxidant property usually studied related to the polyphenols and fl avonoids present in the extract but present finding concluded that S. androgynus giving hint even potential proteins can also show responsible action effective against free radical mediated disease.

Antioxidant activity of protein hydrolysates from raw and heat-treated yellow string beans (Phaseolus vulgaris L.)

Nowadays, legume plants have been considered not only a source of valuable proteins necessary for the proper functioning and growth of the body but also a source of bioactive compounds such as bioactive peptides, that may be benefi cial to human health and protect against negative change in food. The aim of this study was to investigate the effect of heat treatment on the release of antioxidant peptides obtained by hydrolysis of the yellow string beans protein. The antioxidant properties of the hydrolysates were evaluated through free radical scavenging activities (DPPH and ABTS) and inhibition of iron activities (chelation of Fe2+). The results show that the heat treatment had infl uence on both increased peptides content and antioxidant activity after pepsin hydrolysis of string bean protein. The peptides content after protein hydrolysis derived from raw and heat treated beans were noted 2.10 and 2.50 mg·ml-1, respectively. The hydrolysates obtained from raw (PHR) and heat treated (PHT) beans showed better antioxidant properties than protein isolates (PIR and PIT). Moreover, the hydrolysates obtained from heat treated beans showed the higher ability to scavenge DPPH
(46.12%) and ABTS+• (92.32%) than obtained from raw beans (38.02% and 88.24%, correspondingly). The IC50 value for Fe2+ chelating ability for pepsin hydrolysates obtained from raw and heat treatment beans were noted 0.81 and 0.19 mg·ml-1, respectively. In conclusion, the results of this study showed that the heat treatment string beans caused increase in the antioxidant activities of peptide-rich hydrolysates.

Thiamine losses during storage of pasteurised and sterilized model systems of minced chicken meat with addition of fresh and oxidized fat, and antioxidants

Background. The aim of the study was to determine the effect of pasteurisation and sterilization of model systems of minced chicken meat in the presence of low or high-oxidised pork lard, soy and sunfl ower oil, as well as casein hydrolysate and rosemary extract, on losses of thiamine in model systems.
Material and methods. In the samples, the thiamine content was analysed periodically by thiochromium method, as well as rate of lipid oxidation based on measurement of peroxide value (PV) by iodometric method and p-anisidine value (AV) by spectrophotometric method.
Results. It was observed that the thiamine losses in model systems of minced chicken after pasteurisation (61-71%) were higher than after sterilization (57-67%). Introduction of high-oxidised fat increased the total thiamine losses both during thermal processing and storage of meat samples (to 23%). A strong relationship was established between thiamine losses and rate of fat oxidation. The lowest total thiamine losses were observed in the samples with low-oxidised pork lard. Antioxidant addition (rosemary extract or casein hydrolysate) into meat samples limited the thiamine losses. However, the effect depended on oxidation of fat that was mixed with meat. In the samples with low-oxidised fat, higher protective effect was found for rosemary extract (7-11%). In the samples with high-oxidised fat, casein hydrolysate was superior to rosemary extract (14%).
Conclusions. In order to increase the stability of thiamine in pasteurized or sterilized meat products with fats, the infl uence of fat type and its oxidative stability should be taken under consideration. Moreover, the addition of rosemary extract or casein hydrolysate has impact on the thiamine losses since it slows down lipid oxidation to a signifi cant extent.

Infl uence of the marinating type on the morphological and sensory properties of horse meat

Background. The aim of this study was to explore the infl uence of acid, alkaline and water-oil marinating on morphological changes and sensory properties of horse meat (m. Longissimus dorsi).
Material and methods. Nine samples (C – control stored in air, AL – alkaline marinated in 2% polyphosphates and 2% sodium chloride brine solution, AC – acid marinated in 2% sodium lactate and 2% sodium chloride brine solution, WO – marinated in water-oil emulsion (50/50) contained and 2% sodium chloride and SC – marinated in 2% sodium chloride brine solution) were examined. After 24 h and 48 h of marinating changes in morphology of marinated meat, pH and sensory properties of raw and roasted samples were established.
Results. It was determined that sensory properties (aroma, fl avor and tenderness) after roasting were classifi ed as follows: AL48 > AL24 > AC24 > AC48 > SC48 > SC24 > WO24 > WO48 > С. Meat tenderness in AL48, AL24, AC24 and AC48 showed better results due to stronger morphological changes in connective and muscle tissues. Alkaline solutions were more suitable for horse meat marinating compared to acid solutions and the possible reason for strong action of alkaline solutions was lower internal meat pH.
Conclusions. Alkaline marinating should be conducted for 24 h because after 48 h the meat acquires a soft and unusually tender texture. Water-oil marinating was not appropriate for horse meat.

Properties of probiotics and encapsulated probiotics in food

Probiotics are microorganisms which confer health benefi ts upon application in suffi ciently-high viable cell amounts. Probiotics are typically members of Lactobacillus and Bifidobacterium species commonly associated with human gastrointestinal tracts. In the recent past, there has been a rising interest in producing functional foods containing encapsulated probiotic bacteria. Recent studies have been reported using dairy products like cheese, yogurt and ice cream as food carrier, and non-dairy products like meat, fruits, cereals, chocolate, etc. However, the industrial sector contains only few encapsulated probiotic products. Probiotics have been developed by several companies in a capsule or a tablet form. The review compiles probiotics, encapsulation technology and cell life in the food matrices.

Eff ect of probiotics and thyme essential oil on the essential amino acid content of the broiler chicken meat

Background. Differences in the types and percentages of essential amino acids (EAAs) in food could infl uence the value of protein consumed and proteins with a high content of EAAs are the most important components of poultry meat. The use of probiotics for meat and carcass quality improvement has been questioned, while feed supplementation with thyme essential oil (TEO) could be considered as useful natural supplement to be applied in the poultry industry to improve meat quality.
Material and methods. Day-old broilers Ross 308 (n = 400) were randomly divided into four groups based on the feed supplement as follows: control, probiotics 0.05%, TEO 0.05% and combination of probiotics and TEO, while the fattening period was 42 days. Six birds of both sexes from each group were selected as a sample, slaughtered and then stored (–18°C) for 6 months till the analysis. The muscular homogeneous sample (50 g) from the breast and thigh of each sample bird was analysed by the Fourier Transform Infrared Spectroscopy method using the device Nicolet 6700. The essential amino acids content was determined and the quality indicators include chemical score, amino acid score, EAA index and biological value were calculated.
Results. The obtained results show that for all the tested EAAs of the breast and thigh muscles, the content numerically increased gradually and progressively within the groups as the control scored the minimum followed by the probiotics group, then the combination group and fi nally the TEO group which scored the highest results.
Conclusion. It can be concluded that the TEO promoted the increase of all the EAAs and consequently the quality indicators with signifi cant different compared with the control group and signifi cantly different for some EAAs and quality indicators compared with the probiotics group and the combination group.