Effect of different β-glucans on the gelatinisation and retrogradation of rice starch

Four β-glucan preparations, i.e., curdlan (CL), oat (OG), barley (BG) and yeast (YG) β-glucans, were compared for their effects on the gelatinisation and retrogradation of rice starch (RS). Rapid visco-analysis (RVA) showed that addition of any of these β-glucans significantly increased the peak, breakdown, final, and setback viscosities of RS, whereas the pasting temperatures were significantly decreased by OG or CL addition, but were unaffected by BG or YG addition. Differential scanning calorimetry (DSC) demonstrated that all the β-glucans had a negligible effect on the onset (T_o), peak (T_p), and conclusion (T_c) temperatures but slightly decreased the gelatinisation enthalpy (△H₁) of RS. Storage of all the gels at 4 °C resulted in a marked decrease in the T_o, T_p, T_c, and melting enthalpy (△H₂) values. The retrogradation ratio (△H₂/△H₁) and the phase transition temperature range (T_c–T_o) of all the gels increased with storage time. Dynamic viscoelastic measurements revealed weak gel-like behaviour of all the gels, in which their storage modulus (G′) increased and their loss tangent (tan δ) decreased during storage. Steady flow tests illustrated time-dependent shear-thinning (thixotropic) behaviour of all the gels. The hysteresis loop area and the gel hardness increased with storage time. However, the rate and extent of retrogradation and the rheological and textural changes of the RS gels were reduced by addition of any of these β-glucans. The extent of the aforementioned effects differed among the different β-glucan preparations, generally in the order OG ≈ BG > CL ≈ YG.     

Effect of γ-irradiation on physical quality attributes and identification properties of different sauces

Gamma-irradiated (0, 1, and 10 kGy) ketchup (KTP), barbeque sauce (BBQ), and sweet chili sauce (SWC) were identified using photostimulated-luminescence (PSL) and thermoluminescence (TL) analysis and characterized for physical properties like Brix, consistency, and color. PSL-based screening showed negative results for all nonirradiated samples, while intermediated results were found for irradiated samples. Routine density separation method for mineral extraction provided better TL results; however, alkaline and acid hydrolysis could ease the process with acceptable results. A slight decrease in consistency of all the samples was observed. Brix of KTP remained unchanged, while increase of same was obvious in BBQ and SWC following irradiation. The Hunter L* value of the γ-irradiated sauces decreased except SWC samples, and the a* and b* values showed a general increase compared to the non-irradiated samples. The studied methods have potential to successfully identify and characterize the irradiated sauces for technical and regulatory requirements.     

HS-SPME/GC–MS and chemometrics for the classification of Balsamic Vinegars of Modena of different maturation and ageing

Head space solid-phase microextraction (HS-SPME) coupled with GC–MS analysis has been applied for the determination of the characteristic volatile profile of Balsamic Vinegar of Modena (BVM) with the aim to distinguish the less matured products (matured in wooden barrels for at least 60 days) from the aged ones (aged in wooden barrels for at least 3 years). Coupling the HS-SPME/GC–MS analysis data with multivariate statistical techniques, such as Principal Components Analysis (PCA) and Classification Trees (CT), it has been possible to classify BVMs on the basis of different maturation and ageing. A matured BVM presents an aromatic profile characterised by high contents of 3-methyl-1-butanol, 4-ethyl-phenol, and 3-methyl-1-butanol acetate, while an aged BVM is characterised by a prevalence of ethyl acetate, ethyl acetoacetate, furans, 2,3-butanediol and 2,3-butanediol acetate. This work represents a first attempt to classify Balsamic Vinegars of Modena on the basis of their maturation and ageing.     

Isomerisation kinetics and antioxidant activities of β-carotene in carrots undergoing different drying techniques and conditions

Carrots are known as a natural source of β-carotene. In order to preserve the latter, carrots must generally be processed, and drying is one of the most common methods for processing carrots. During drying β-carotene in carrots suffers degradation. β-Carotene degradation is generally due to thermal degradation and isomerisation. In this work, the drying kinetics as well as the isomerisation kinetics and antioxidant activities of β-carotene in carrots undergoing hot air drying, vacuum drying and low-pressure superheated steam drying (LPSSD) were determined within the temperature range of 60–80 °C and, in the case of vacuum drying and LPSSD, at a pressure of 7 kPa. A high performance liquid chromatography (HPLC) method was used to determine the β-carotene contents and its isomerisation kinetics, while the antioxidant activities of various combinations of all-trans- and cis-forms of β-carotene in carrots were evaluated using the Trolox equivalent antioxidant capacity (TEAC) assay.     

The effect of different cooking procedures on microbiological and chemical quality characteristics of Tekirdağ meatballs

In this research, the effects of different cooking processes (grilling, oven, and microwave cooking) on microbial flora and chemical composition of the raw and cooked meatballs as consumed in Tekirda? were investigated. Microbial flora of the raw meatballs was as follows: total bacteria, 6.02 x 10(6) cfu/g; psychrophilic bacteria, 1.3 x 10(5) cfu/g; yeast and mould, 2.4 x 10(5) cfu/g; coliforms, 1.1 x 10(5) cfu/g; Escherichia coli, 1.0 x 10(2) cfu/g; total staphylococcae, 3.3 x 10(2) cfu/g; Staphylococcus aureus, 85 cfu/g. While Salmonella was found in only one sample, none of the samples contained Clostridium perfringens. The cooking processes clearly decreased the microbial flora (2-3 log cycles in grilling (71 degrees C) and oven-cooked (79 degrees C), 3-4 log cycles in microwave (97 degrees C) heating) of the meatballs. However, because of the crust formation and high moisture losses from the meatball surface in microwave heating, some sensorial defects were observed in the final product. Also, fat and moisture losses were higher in microwave cooking compared to the other cooking processes. In conclusion, it is advised to use slightly higher temperatures than used in the grilling or conventinal cooking procedures to increase microbial quality of the meatballs studied in this research.     

Carcass composition and meat quality of three different Iberian×Duroc genotype pigs

Carcass composition and meat quality of Longissimus dorsi (LD) and Biceps femoris (BF) muscles from three different Iberian×Duroc genotype pigs were studied: GEN1: ♂ Iberian×♀ Duroc1; GEN2: ♂ Duroc1×♀ Iberian; GEN3: ♂ Duroc2×♀ Iberian. Duroc1 (DU1) were selected for the manufacture of dry-cured meat products while Duroc2 (DU2) were pigs selected for meat production, with high percentages of meat cuts and low carcass fat. Genotype had a significant effect on the differences found while sex had not. GEN2 showed the highest weights at days 180 and 238 of weaning and the highest slaughter weights (day 316) followed by GEN3, while the lowest weights were found in GEN1. GEN3 had well conformed carcasses in comparison with GEN1 and GEN2, since GEN3 showed the highest percentages of ham and loin and the highest weight of loin as well as the lowest back and ham fat thickness. However, the use of DU2 pigs in the cross with Iberian had negative effects on meat quality, as GEN3 gave the worst meat quality in both muscles, postmortem pH, cook and drip loss, and colour and the lowest percentages of intramuscular fat (IMF). In subcutaneous fat (SCF), GEN3 had higher percentages of polyunsaturated fatty acids (PUFA) than GEN2, while GEN2 had higher saturated fatty acids (SFA) levels. In LD, IMF from GEN3 showed the highest percentage of MUFA and PUFA; while the fatty acid profile of GEN2 was more saturated. BF muscle showed similar trends, but not significantly so. On the other hand, few differences were found between reciprocal crosses (GEN1 vs. GEN2). GEN2 showed higher IMF in LD than GEN1, agreeing with their carcass weight. As a result, GEN1 had a fatty acid profile of IMF in the LD that was more unsaturated.     

Physicochemical characteristics and in vitro bile acid binding and starch digestion of β-glucans extracted from different varieties of Jeju barley

Physicochemical properties of six different varieties of barley and their β-glucans were evaluated along with in vitro bile acid binding and starch digestibility for health beneficial effects. β-Glucan concentrations in less-hulled, beer, black, waxy-naked, naked, and blue barley were 3.44, 3.46, 6.08, 6.75, 6.45, and 5.91%, respectively. Viscosity of waxy-naked barley flour was the highest. While the yield of β-glucan from waxy-naked barley after extraction was 95.49%, less-hulled barley was 70.09%. As the increase of β-glucan purification, in vitro bile acid binding was increased when compared with cholestyramine and cellulose. In vitro starch digestibility of barley flour and the mixture of potato starch with β-glucan were increased by heat and β-glucan concentration. Estimated glycemic index (GI) calculated based on in vitro starch digestibility was decreased by increasing β-glucan. These results suggest that the physicochemical properties of barley were dependent on the variety of barley and especially β-glucan was involved.     

Influence of different β-glucans on the physical and rheological properties of egg yolk stabilized oil-in-water emulsions

The objective of this study was to obtain additional information on the influence of different β-glucan preparations, i.e. curdlan (CL), barley (BG), oat (OG), and yeast (YG) β-glucans, on the physical and rheological properties of egg yolk stabilized oil-in-water emulsions containing 20% oil. The emulsion without β-glucan (REF) was also prepared as a reference. Addition of CL and OG increased emulsion oil droplet sizes, whereas BG and YG showed no effect. Emulsion microstructures revealed that β-glucans induced flocculation of the oil droplet in the following order: CL > BG ≈ OG > YG. Dynamic oscillatory shear tests indicated that all emulsions exhibited weak gel-like characteristics which were enhanced by β-glucans addition as evidenced by an increase in G′ and a decrease in tan δ values. Flow tests showed that β-glucans enhanced thixotropy and yield stress of the emulsions. Stability tests demonstrated that β-glucans addition improved creaming stability of the emulsions during storage possibly due to an increase in viscosity of the continuous phase and/or a formation of a three-dimensional droplet network. CL exhibited the most pronounced effects on the aforementioned properties of emulsions compared to the other β-glucans tested. YG gave emulsion with higher viscoelastic properties and yield stress but lower stability than those made with BG or OG, indicating complex relationship between rheology and stability of these emulsion systems.     

Up-milling and down-milling wood with different grain orientations – theoretical background and general appearance of the chips

Peripheral milling with up-milling and down-milling techniques is very well known from a geometrical point of view. However, in processing anisotropic materials such as wood these geometrical aspects imply relevant differences when machining. In fact milling anisotropic materials leads to different cutting geometries when up-milling or down-milling and when changing the depth of cut. This results in a relative orientation of the grain depending on the process adopted. In this paper the geometrical interactions between tool and wood grain have been analysed theoretically and supported by experimental evidence. To achieve this result, Douglas fir has been processed with different depths of cut and grain orientations, the resulting chips have been collected and analysed. The experiments show how a shift of the cutting phenomenon and the chip type can be observed to support the theoretical background.     

Effects of different vinification technologies on physico-chemical properties and antioxidant activity of ‘Falanghina’ and ‘Bombino bianco’ wines

The present research was aimed to compare the traditional white vinification with a combined cryomaceration–vinification in reductive conditions, by evaluating their effects on chemical and physical indices and on antioxidant compounds of ‘Falanghina’ and ‘Bombino bianco’, two wine grape cultivars of southern Italy. According to the results, the two cultivars showed similar behaviour in response to the same vinification protocol. The processing conditions mainly affected physico-chemical characteristics such as titratable acidity, pH, SO₂, tartaric and malic acids, phenolic concentrations, and antioxidant activity. Titratable acidity decreased with cryomaceration due to the tartrate precipitation, whereas the malic acid was greatly extracted from pulps and skins. In the reductive conditions applied, the SO₂ was protected by the presence of ascorbic acid; thus, the wines exhibited higher free/total SO₂ ratio. Cryomaceration combined with vinification in reductive conditions allowed a greater extraction of phenolic compounds from skins and, consequently, a greater antioxidant activity compared to the traditional winemaking. This behaviour was due to both the protection exerted by the low temperatures and the solubilisation of proanthocyanidins and flavans reactive with vanillin favoured by the high free SO₂ content.     

Flux and transmission of β-casein during cold microfiltration of skim milk subjected to different heat treatments

Raw skim milk was subjected to different heat treatments: thermization (65°C, 20 s), pasteurization (72°C, 15 s), and no heat treatment (milk was microfiltered using 1.4-µm membranes at 50°C for bacteria removal; 1.4 MF). The milk (thermized, pasteurized, and 1.4 MF) was cooled and stored at 2°C until processing (at least 24 h) with cold (～6°C) microfiltration using a benchtop crossflow pilot unit (Pall Membralox XLAB 5, Pall Corp., Port Washington, NY) equipped with 0.1-µm nominal pore diameter ceramic Membralox membrane (ET1-070, α-alumina, Pall Corp.). The flux was monitored during the process, and β-casein transmission and removal were calculated. The study aimed to indicate the conditions that should be applied to maximize β-casein passage through the membrane during cold microfiltration (5.6 ± 0.4°C) of skim milk. The proper selection of heat treatment parameters (temperature, time) of the feed before the cold microfiltration process will increase β-casein removal. It is not clear whether the difference in β-casein transmission between 1.4 MF, thermized, and pasteurized milk results from the effect of heat treatment conditions on β-casein dissociation from the casein micelles or on passage of β-casein through the membrane. The values of the major parameters (permeation flux and tangential flow velocity, through the wall shear stress) responsible for a proper membrane separation process were considerably lower than the critical values. It seems that the viscosity of the retentate has a great effect on the performance of the microfiltration membranes for protein separation at refrigerated temperatures.     

Recombinant production of a hard-to-express membrane-bound cytochrome P450 in different yeasts—Comparison of physiology and productivity

Cytochrome P450s comprise one of the largest protein superfamilies. They occur in every kingdom of life and catalyse a variety of essential reactions. Their production is of utmost interest regarding biotransformation and structure-function elucidation. However, they have proven hard to express due to their membrane anchor, their complex co-factor requirements and their need for a redox-partner. In our study, we investigated and compared different yeast strains for the production of the plant cytochrome P450 chalcone 3-hydroxylase. To our knowledge, this is the first study evaluating different yeasts for the expression of this abundant and highly significant protein superfamily. Saccharomyces cerevisiae and three different strains of Pichia pastoris expressing chalcone 3-hydroxylase were cultivated in controlled bioreactor runs and evaluated regarding physiological parameters and expression levels of the cytochrome P450. Production differed significantly between the different strains and was found highest in the investigated P. pastoris MutS strain KM71H where 8 mg P450 per gram dry cell weight were detected. We believe that this host could be suitable for the expression of many eukaryotic, especially plant-derived, cytochrome P450s as it combines high specific product yields together with straightforward cultivation techniques for achieving high biomass concentrations. Both factors greatly facilitate subsequent establishment of purification procedures for the cytochrome P450 and make the yeast strain an ideal platform for biotransformation as well.     

Size of native and heated casein micelles,content of protein and minerals in milk from Norwegian Red Cattle—effect of milk protein polymorphism and different feeding regimes

Milk samples of 59 cows of the Norwegian Red Cattle breed receiving three different supplementary concentrates, were analysed for genotypes of caseins and whey proteins, the content of different milk salts (Ca²⁺, Ca, Mg and citrate), the content of total protein, casein and whey protein and the mean micellar size of native and heated casein micelles. The genotype of α_s1-casein had a statistically significant effect on the content of protein and casein, and the content of whey protein and the casein number were significantly influenced by different feeding regimes, and the content of citrate. The mean size of native and heated casein micelles was significantly influenced by the feeding regimes, genotype of α_s1-casein (native mean size only) and κ-casein, pH and the content of casein, whey protein and casein number. The heat-induced changes in mean micellar size were significantly affected by the calcium ion activity which accounted for approximately 40% of the total variation.     

Effects of lipid supplementation on the yield and composition of milk from cows with different β-lactoglobulin phenotypes

Responses to lipid supplementation differ between dairy breeds and genetic lines suggesting nutrition by genotype interactions. β-Lactoglobulin phenotype is associated with changes in yield and composition of milk. The response of cows with different β-lactoglobulin phenotypes to lipid supplementation has not been examined. Furthermore, we examined whether lipid supplementation alters milk protein composition. By using a randomized block design, we fed Holstein cows for 3 wk either a control diet containing 2.8% crude fat (n = 19) or an experimental diet that was supplemented with 4.2% tallow (n = 20). Before randomization, all cows were fed the supplemental tallow diet for at least 2 wk. Dry matter intake, body weight, milk yield, and milk composition were measured in the last week before and during the experimental period. Feeding supplemental tallow increased dry matter intake and yields of milk and milk components, including casein content, without decreasing milk component content or altering milk protein composition. On the low-fat control diet, cows with the β-lactoglobulin allele B had a greater milk and milk component yield than cows with the A allele, whereas no differences by β-lactoglobulin phenotype were observed in cows on the tallow supplement diet. Our results suggest that cows that differ in β-lactoglobulin phenotype respond differently to a low-fat diet and that feeding cows 4.2% of additional tallow increases milk yield without affecting milk component content and milk protein composition.     

Influence of different extraction conditions on the detection of glycinin and β-conglycinin in model processed foods by ELISA

ABSTRACT

The presence of undeclared soy proteins in food can cause severe reactions in soy allergic individuals. The extraction of target proteins from processed foods is a crucial step in allergen detection by immunoassays, as only successfully extracted target proteins can be detected by the specific antibodies. The effectiveness was studied of different conditions (type of buffer, temperature and time of incubation) on the extraction of total protein, and concentration of glycinin and β-conglycinin from different food matrices. The yields were determined using a soy protein isolate and three processed foods (sausage, bread and pâté) incurred with soy proteins. The yields were affected by the processing of analysed products and the composition and pH of the extraction buffers. Neutral and alkaline buffers (pH from 7.4 to 10.6) exhibited good protein extraction capacity and detectability of the specific target proteins. Denaturing additives and highly alkaline buffer (pH 12) extracted more crude protein but they were incompatible with the ELISA assay. Overall, the best results were obtained using phosphate (pH 7.4) and Tris/HCl (pH 8.5) buffers in the presence of 0.5 M NaCl. Crude protein yield of food extracts did not correlate with that of glycinin and β-conglycinin, whereas a good relationship was found between the yields of the two proteins.     

Detection of 5-hydroxymethyl-2-methyl-3(2H)-furanone and of α-dicarbonyl compounds in reaction mixtures of hexoses and pentoses with different amines

Summary In reaction mixtures of hexoses with primary amines, heated at pH 5 and 7, distinctly higher amounts of fragmentation products are formed in the upper pH range. To estimate the amount of fragmentation, all-dicarbonyl compounds which react witho-phenylenediamine to quinoxaline derivatives were recorded. For the first time the-dicarbonyl intermediates in a pentose amine reaction mixture were determined and the formation of 2,3,4-pentantrione was detected. The 1,4-dideoxyosone was formed from hexoses and pentoses in higher yields in the presence of-amino acids, i.e. when Strecker degradation could take place. 5-Hydroxymethyl-2-methyl-3(2H)-furanone was identified as a new hexose product of Strecker degradation, and its structure established unequivocally by independent synthesis as well as by¹H and¹³C NMR.

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Nachweis von 5-Hydroxymethyl-2-methyl-3(2H)-furanon und von -Dicarbonylverbindungen in Reaktionsgemischen von Hexosen und Pentosen mit verschiedenen Aminen

Zusammenfassung In Reaktionsgemischen von Hexosen mit priären Aminen, die bei pH 5 und pH 7 erhitzt wurden, findet man im höheren pH-Bereich wesentlich größere Mengen an Fragmentierungsprodukten. Zur Abschätzung des Fragmentierungsanteils werden alle-Di-carbonylverbindungen herangezogen, die mito-Pheny-lendiamin im Umsetzungsgemisch zu Chinoxalinen reagieren. Erstmals werden die-Dicarbonyl-Zwischenstu-fen in Pentose-Amin-Reaktionsans ätzen untersucht und die Bildung des 2,3,4-Pentantrions nachgewiesen. Interessant ist, daß bei Hexosen und Pentosen das 1,4-Didesoxyoson in wesentlich größeren Mengen entsteht, wenn -Aminosäuren an der Umsetzung beteiligt sind, d.h. wenn ein Strecker-Abbau stattfinden kann. 5-Hydroxymethyl-2-methyl-3(2H)-furanon wird als neues Hexoseprodukt des Strecker-Abbaus identifiziert. Die Absicherung der Struktur erfolgt durch Synthese und NMR-Un-tersuchungen.

     

Structure–property relationship of different types of polyester industrial yarns

Four major types of polyester industrial yarns (1000 Denier) which are used commercially were studied for their key structural parameters. An attempt has been made to establish a relationship between morphology and properties of these yarns. High tenacity (HT) polyester yarn has the highest birefringence, amorphous orientation, and long period but is relatively less crystalline. High shrinkage characteristic of HT polyester yarn can be accounted for its higher amorphous orientation. High modulus low shrinkage (HMLS) polyester yarn has higher crystallinity and crystal size compared to HT yarn. Fraction of tie molecules of these yarns has been calculated and found that low shrinkage (LS) and super low shrinkage (SLS) yarns have lesser tie molecules. These LS and SLS yarns are tailor-made to achieve lower shrinkage and at the same time maintaining a good level of tenacity. This is achieved with lower amorphous orientation in the final drawn yarn structure. Amorphous orientation was found to have stronger influence than any other structural parameter on the key yarn properties like modulus, tenacity, elongation, and shrinkage.     

Influence of slaughter season and sex on fatty acid composition, cholesterol and α-tocopherol contents on different muscles of Barrosã-PDO veal

The influence of slaughter season and sex on intramuscular total lipids (ITL) neutral lipid (NL) and phospholipid (PL) compositions, cholesterol and α-tocopherol contents were evaluated in Biceps femoris (Bf), Longissimus dorsi (Ld) and Supraspinatus (Ss) muscles from 92 Barrosã-PDO (Protected Denomination of Origin) calves. ITL content in Bf muscle was affected by slaughter season and sex whereas NL content was only affected by slaughter season. Neither sex nor slaughter season influenced cholesterol and α-tocopherol contents in the muscles under study. Concerning NL composition, sex was an important source of variation on the proportions of total SFA and MUFA in all muscles. Irrespective of the considered muscle, males had higher total SFA but lower total MUFA and MUFA/SFA contents than females. Slaughter season influenced C18:2 cis-9 trans-11 (CLA) content in Bf (P < 0.01) and in Ss muscles (P < 0.05) with calves slaughtered in autumn showing higher values than their counterparts. Total MUFA, n-3 PUFA and n-6/n-3 ratio contents in Ld muscle were also affected by slaughter season. Regarding PL composition, slaughter season × sex interaction affected total SFA, PUFA/SFA and n-6 PUFA contents in Bf and Ss muscles. In addition, this interaction influenced total MUFA (P < 0.05) in Bf muscle and total PUFA (P < 0.01) in Ss muscle. CLA content in PL from Ld was influenced by sex (P < 0.05) and by slaughter season (P < 0.01), with females slaughtered in autumn presenting the highest content. These results clearly indicate that sex and slaughter season are important factors that influence the fatty acid composition of Barrosã-PDO veal.