Investigation and Modeling of Electrical Stunning Parameters of Turkey Using Response Surface Methodology

Abstract: The aim of this work is to evaluate the effects of electrical stunning parameters of turkey on the quality of steak and stew using the response surface methodology. 1584 turkeys were used for the study. The parameters tested were the voltage and pulse. The responses were the sensory quality of steak and stew. The rejection rate varies between 0.23% (steak female) and 56.06% (female stew). Results show that it is possible to obtain a low rejection rates (< 1% for the steak of male turkey) at a voltage of 50 Volts and pulse of 7. In comparison of pulse, voltage remains the most important factor. The optimal conditions selected for the total output of the process obtained from the analysis of the response surfaces are: voltage, from 45 to 47 Volts; pulse from 6.5 to 7 and voltage from 50 to 52 Volts; pulse from 6.8 to 7, respectively for female and male turkeys. Under these experimental conditions, the rejection rates range from 0.23% to 0.80% and from 11.93% to 13.27% respectively for steak and stew. The results show that the voltage and pulse are both the parameters meaning on the global quality of steak and stew

Utjecaj različitih podloga na hranjiva i funkcionalna svojstva mikroalgi upotrijebljenih za obogaćivanje sira tipa ricotta

Research background. Microalgae represent an emergent sustainable source of bioactive compounds such as antioxidants, vitamins, minerals and polyunsaturated fatty acids that can ameliorate the nutritional characteristics of foods. The biochemical composition of microalgae could be modulated by varying the culture conditions to enhance the accumulation of biomolecules of interest. The aim of this work is to optimise the nutri-functional properties of two microalgae that can be used in food production. Experimental approach. Nannochloropsis gaditana L2 and Chlorella sp. SM1 were screened for growth, biochemical composition and radical scavenging activity employing four different growth media (algal, BG-11, f/2 and Conway) with different nutrient composition. The feasibility of using Chlorella sp. SM1 cultivated in BG-11 medium, in an under-investigated Mediterranean dairy product ricotta cheese and its effect on the sensory attributes was investigated. Additionally, Arthrospira platensis was used as reference in sensory analysis. Results and conclusions. Nitrate- and phosphate-rich media (BG-11 and algal) enhanced the biomass productivity. However, the highest lipid production (23.10 and 11.86 mg/(L·day) by strains SM1 and L2 respectively) and carbohydrate content (34.79 and 44.84% by SM1 and L2 respectively) were obtained with the nitrate-deficient f/2 medium. Regardless of the used medium, the lipid profile of Chlorella sp. SM1 and N. gaditana L2 remained adequate for different applications with >50% C16-18 as the main fatty acids. Significant increase in oleic acid (C18:1) content was recorded in response to nitrogen deficiency, being the highest in SM1 in f/2 medium (34%). Nitrogen deficiency was also found to enhance phenolic compound (expressed as gallic acid equivalents, 48.8 and 35.1 mg/g in SM1 and L2 respectively) and carotenoid contents (2.2 and 2.0 mg/g in SM1 and L2 respectively). Due to its interesting antioxidant potential, Chlorella sp. SM1 was used at different mass fractions (0.2, 1 and 1.5%) to enrich the ricotta cheese. The sample with 0.2% Chlorella sp. SM1 was found to give the most appreciated product. Novelty and scientific contribution. This study presents the production of an innovative ricotta cheese using Chlorella sp. as a functional ingredient, without altering the manufacturing procedure, while maintaining acceptable sensorial characteristics. The biochemical composition of the used strains varied depending on the culture medium composition, which enabled the accumulation of phytonutrients of interest.Pozadina istraživanja. Mikroalge su sve češći održivi izvor bioaktivnih spojeva, poput antioksidansa, vitamina, minerala i polinezasićenih masnih kiselina, kojima se mogu poboljšati nutritivna svojstva hrane. Biokemijski se sastav mikroalgi može izmijeniti promjenom sastava podloge za uzgoj, s ciljem povećanja prirasta željenih biomolekula. Svrha je ovoga rada bila optimirati hranjiva i funkcionalna svojstva dviju vrsta mikroalgi koje se mogu primijeniti u proizvodnji hrane. Eksperimentalni pristup. Analizirani su rast, biokemijski sastav te sposobnost uklanjanja slobodnih radikala mikroalgi Nannochloropsis gaditana L2 i Chlorella sp. SM1 uzgojenih u četiri podloge različitog sastava (hranjiva podloga za uzgoj algi, BG-11, f-2 i hranjiva podloga Conway). Ispitana je mogućnost primjene alge Chlorella sp. SM1 uzgojene u BG-11 podlozi u proizvodnji sira tipa ricotta, mediteranskog mliječnog proizvoda koji je slabo istražen, te njezinog utjecaja na senzorska svojstva sira. Uz to, mikroalga Arthrospira platensis upotrijebljena je za izradu kontrolnog uzorka za senzorsku analizu. Rezultati i zaključci. Proizvodnja se biomase povećala u podlogama bogatim nitratima i fosfatima (BG-11 i hranjiva podloga za uzgoj algi). Međutim, najveća proizvodnja lipida (dnevno 23,10 mg/L u soju SM1 i 11,86 mg/L u soju L2) i najveći udjel ugljikohidrata (34,79 % u soju SM1 i 44, 84 % u soju L2) postignuti su uzgojem u podlozi f/2 siromašnoj nitratima. Bez obzira na sastav podloge, sastav lipida u mikroalgama Chlorella sp. SM1 i N. gaditana L2, s više od 50 % C16-18 kao glavnim masnim kiselinama, bio je prikladan za različite primjene. Nedostatak dušika doveo je do znatnog povećanja udjela oleinske kiseline (C18:1), i to najviše u soju SM1 uzgojenom u podlozi f/2 (34 %). Također su opaženi povećani udjeli fenolnih spojeva (48,8 mg/L u soju SM1 i 35,1 mg/g u soju L2, izraženo kao ekvivalent galne kiseline) i karotenoida (2,2 mg/g u soju SM1 i 2,0 mg/g u soju L2). Zbog svog zanimljivog antioksidacijskog potencijala, mikroalga Chlorella sp. SM1 primijenjena je u različitim masenim udjelima (0,2; 1 i 1,5 %) za obogaćivanje sira tipa ricotta. Proizvod s najboljiim karakteristikama dobiven je s dodatkom 0,2 % ove mikroalge. Novina i znanstveni doprinos. U radu je prikazana proizvodnja novog sira tipa ricotta s dodatkom mikroalge Chlorella sp. kao funkcionalnim sastojkom, pri čemu se nije mijenjao postupak proizvodnje, a zadržane su prihvatljive senzorske značajke sira. Biokemijski je sastav korištenih sojeva mikroalgi ovisio o sastavu hranjive podloge, pa je time bilo moguće povećati proizvodnju željenih fitonutrijenata

Chemical Composition, Antioxidant and Antimicrobial Activities of Thymus capitata

The chemical composition, antioxidant and antimicrobial activities, and the preservative effect of Thymus capitata essential oil against Listeria monocytogenes inoculated in minced beef meat were evaluated. The essential oil extracted was chemically analyzed by gas chromatography-mass spectrometry. Nineteen components were identified, of which carvacrol represented (88.89%) of the oil. The antioxidant activity was assessed in vitro by using both the DPPH and the ABTS assays. The findings showed that the essential oil exhibited high antioxidant activity, which was comparable to the reference standards (BHT and ascorbic acid) with IC50 values of 44.16 and 0.463 μg/mL determined by the free-radical scavenging DPPH and ABTS assays, respectively. Furthermore, the essential oil was evaluated for its antimicrobial activity using disc agar diffusion and microdilution methods. The results demonstrated that the zone of inhibition varied from moderate to strong (15–80 mm) and the minimum inhibition concentration values ranged from 0.32 to 20 mg/mL. In addition, essential oil evaluated in vivo against Listeria monocytogenes showed clear and strong inhibitory effect. The application of 0.25 or 1% (v/w) essential oil of T. capitata to minced beef significantly reduced the L. monocytogenes population when compared to those of control samples (P-value  <0.01)

Ruta chalepensis L. Essential Oil: A New Antisprouting Agent for Potatoes Bioconservation

The main concern of this work was to find a new biological antisprouting product for potatoes during storage. Ruta chalepensis L. essential oil (RCEO) was for the first time used as a potential sprouting inhibitor for potatoes. To confirm RCEO antisprouting effect, evolution of sprout length and weight loss of potato tubers was determined during a storage period of six weeks under three RCEO different treatments (2%, 4%, and 6%). Sprout final weight was also computed. Then, a screening of RCEO chemical composition was performed. An outstanding antisprouting effect of 6% emulsions concentrations was observed as compared to 2% and 4% emulsions concentrations. Final sprout weight (SW) of untreated samples was 4.66%, while 6% treated samples scored 0.98%. These results were endorsed by high Pearson correlation coefficients (>0.9). Indeed, increasing treatment concentration enhanced the sprout growth inhibition. Identification of RCEO major components showed that 2-undecanone represented 87.18% of total identified components suggesting that this component is the possible active agent of RCEO against potatoes sprouting

Effect of some additives on wheat gluten solubility: a structural approach

International audienceThe effects of KCl, NaCl and cysteine on the solubility in water of partially hydrolyzed gluten were studied at different pH values. As expected, solubility was shown to depend on solution pH. It decreased to reach a minimal value at the isoelectric pH (pH 6) and then it increased. In the presence of additives, the same behaviour was observed with an increase in solubilities values. In fact, an improvement of solubility of 28–30% was observed in the case of KCl and cysteine, while NaCl was much less efficient. The solubilisation effect of such additives was found to decrease with the initial concentration of wheat gluten. The structural investigation, by analysis of the amide I region of the infrared spectra of gluten samples, solubilised in the presence of additives, showed an increase in the proportion of β-turns and extended structures, accompanied by a decrease in the α-helix proportion. Such results confirm and explain the improvement of wheat gluten solubility by enhancing water–protein bonding and reducing protein–protein interactions. Structural changes result in a better accessibility of more water molecules to the protein and in greater hydration and solubilisation effects

Tunisian Milk Thistle: An Investigation of the Chemical Composition and the Characterization of Its Cold-Pressed Seed Oils

In this study, milk thistle seeds growing in different areas in Tunisia were cold pressed and the extracted oils were examined for their chemical and antioxidant properties. The major fatty acids were linoleic acid (C18:2) (57.0%, 60.0%, and 60.3% for the milk thistle seed oils native to Bizerte, Zaghouan and Sousse, respectively) and oleic acid (C18:1) (15.5%, 21.5%, and 22.4% for the milk thistle seed oils originating from Bizerte, Zaghouan and Sousse, respectively). High performance liquid chromatography (HPLC) analysis showed the richness of the milk thistle seed oils (MTSO) in α-tocopherol. The highest content was recorded for that of the region of Zaghouan (286.22 mg/kg). The total phenolic contents (TPC) of Zaghouan, Bizerte, and Sousse were 1.59, 8.12, and 4.73 Gallic Acid Equivalent (GAE) mg/g, respectively. Three phenolic acids were also identified (vanillic, p-coumaric, and silybine), with a predominance of the vanillic acid. The highest value was recorded for the Zaghouan milk thistle seed oil (83 mg/100 g). Differences in outcomes between regions may be due to climatic differences in areas. Zaghouan’s cold-pressed milk thistle seed oil had a better quality than those of Bizerte and Sousse, and can be considered as a valuable source for new multi-purpose products or by-products for industrial, cosmetic, and pharmaceutical utilization

Understanding the Effects of Genotype, Growing Year, and Breeding on Tunisian Durum Wheat Allergenicity. 1. the Baker's Asthma Case

Baker's asthma is a serious airway disease triggered by wheat protein CM3 α-amylase/trypsin inhibitor. The purpose of the present study was to investigate the impact of genotype and crop year on allergen CM3 α-amylase/trypsin inhibitor associated with baker's asthma. A historical series of Tunisian durum wheat (100 accessions), derived from three crop years, was used to compare the amount of CM3 from landraces to advanced cultivars. CM3 protein quantification was assessed after an enzymatic cleavage of the soluble protein extracts on a UPLC/ESI-MS system, using a marker peptide for its quantification. Combined data analysis of variance revealed an important effect of genotype, crop year, and their interaction. The CM3 allergenic proteins were found to significantly vary among studied genotypes, as confirmed by genetic variability, coefficient of variance, heritability, and genetic advance

Understanding the Effects of Genotype, Growing Year, and Breeding on Tunisian Durum Wheat Allergenicity. 2. The Celiac Disease Case

The aim of this study was to compare immunogenic and toxic gluten peptides related to celiac disease (CD). 100 accessions of genotypes selected during the 20th century in Tunisia were in vitro digested and then analyzed by UPLC/ESI-MS technique using an isotopically labeled internal standard. The first MANOVA confirmed a high variability in the content of immunogenic and toxic peptides reflecting high genetic diversity in the germplasm released during the past century in Tunisia, consistently with PCA and clustering analysis results. Our finding showed also important variability in CD epitopes due to growing season’s climate scenarios. Moreover, the second MANOVA revealed significant differences between abandoned and modern cultivars’ CD-related peptide amounts. Although we could not conclude that there was an augment of allergens in newly selected durum wheat lines compared to abandoned ones, we demonstrated that modern genotype peptides were less sensitive to climate variation, which is a useful indicator for wheat breeders