Retrogradation—Digestibility Relationship of Selected Glutinous and Non-Glutinous Fresh and Stale Cooked Rice

This study examined the retrogradation and digestibility relationship of fresh and stale cooked rice of three rice varieties: glutinous (TDK11) and non-glutinous (Doongara and floating rice). The effect of rice variety, degree of milling and retrogradation (staling) of cooked rice on the estimated glycaemic index was determined. Although high-glycaemic index values were obtained for fresh cooked rice of all varieties, staling rice at 4^oC for 24 h showed positive effect on floating rice only, yielding intermediate-glycaemic index. The effect of staling on retrogradation rates was corroborated by changes in x-ray diffraction peaks. The thermal and textural properties of rice samples showed higher pasting temperature, final viscosity, and hardness, and lower peak viscosity and adhesiveness for fresh cooked non-glutinous varieties, which were also significantly affected by degree of milling, in terms of hardness, after retrogradation.     

Relationship Between β-amylase Activity,Steeliness, Mealiness,Nitrogen Content and the Nitrogen Fractions of the Barley Grain

Steely grains tend to have a higher total nitrogen than corresponding mealy grains. β-Amylase activities of different barley varieties appeared to be associated, to different degrees, with steeliness, high total nitrogen content, and high levels of total salt soluble proteins and hordein proteins. The consistent relationship between β-amylase activity and these parameters suggests that β-amylase contents of barley not only reflect genetic differencies in varieties, but also differences in protein type and grain structure. Notwithstanding, the β-amylase content of the grain may not be indicative of the potential of the grain to develop β-amylase activity during malting.     

Reactions of phenolic substances with lysozyme — physicochemical characterisation and proteolytic digestion of the derivatives

Lysozyme was modified by covalent attachment of selected phenolic compounds (m-, o-, p-dihydroxybenzenes, ferulic and gallic acid) at pH 9. The derivatives formed were characterized in terms of their physicochemical and digestion properties. The derivatization was accompanied by a reduction of lysine and tryptophan residues. Moreover, the solubility of the derivatives decreased over a broad pH range and the derivatization increased the hydrophobicity. The isoelectric points were shifted to lower pH values and formation of high molecular weight fractions occurred. In vitro experiments showed that, the peptic digestion of the derivatized lysozyme was adversely affected, whereas the tryptic, chymotryptic and pancreatic hydrolysis seemed to be favoured. The lytic activity of all the resulting lysozyme derivatives was reduced.     

Application of Fast Gas Chromatography–Mass Spectrometry in Combination with the QuEChERS Method for the Determination of Pesticide Residues in Fruits and Vegetables

A fast gas chromatography–mass spectrometry method has been developed for multiresidue determination of up to 56 pesticides in fruits and vegetables in a chromatographic run time of <10 min, using a single quadrupole mass spectrometer operating in selected ion monitoring mode. The well-known acetate-buffering version of the QuEChERS method has been used for sample preparation. Programmable temperature vaporizer injection of 3 μL allowed reaching limits of detection between 0.15 and 15 μg/kg for most compounds in the sample matrices tested. The applicability of the method has been evaluated in apple, orange, carrot, and tomato. Recoveries at three fortification levels (0.01, 0.1 and 0.5 mg/kg) ranged from 70 to 120 % for most compounds, with relative standard deviations below 20 % in all cases. The developed method has been applied to fruit and vegetable samples from different Spanish provinces.     

High Intensity Ultrasound as an Abiotic Elicitor—Effects on Antioxidant Capacity and Overall Quality of Romaine Lettuce

The effect of ultrasound treatment at low acoustic power density (APD) on antioxidant capacity and overall quality of Romaine lettuce was evaluated. Whole leaf lettuce was treated with ultrasound (25 kHz) at APD of 26 W/L for 1–3 min and stored at room temperature for up to 150 h. Quality indices examined included color, texture, total phenolics, antioxidant capacity, and sensory properties. Phenylalanine ammonia-lyase (PAL) activity of lettuce from different treatments was monitored during storage. There were no differences in sample quality attributes between ultrasound treatment and control immediately after treatment. Lettuce treated with ultrasound exhibited an increase in PAL activity after storage for 60 h, resulting in production of phenolic compounds as secondary metabolites and enhancement of antioxidant capacity. Ultrasound-treated samples did not exhibit deterioration during storage, and under certain conditions, it delayed enzymatic browning and maintained better overall quality. A hypothetical model for the effect of low APD ultrasound as an abiotic elicitor on fresh produce was proposed based on the finding of present study and evidence from previous reports on response of cell cultures to ultrasond treatment.     

Characterisation of lady finger batters and biscuits by fluorescence spectroscopy—Relation with density,color and texture

Different properties of lady finger batters were measured using several methods: texture profile analysis, spectrocolorimetry and fluorescence spectroscopy. Firstly, it was shown that no significant ageing of the batter occurred during the first 5 h at 18 °C. Secondly, it was shown that the investigated factors, i.e., egg content, prefoaming duration and aeration velocity and their combination, had a significant effect on the properties of the batter. Thirdly, a good discrimination of batters and of biscuits processed in different conditions could be achieved using NADH and tryptophan fluorescence spectra. Moreover, good correlations between the spectra of batter and the spectra of biscuits were shown. Finally, a relation between fluorescence spectra and macroscopic properties was shown both using CCA and PLS. Using PLS, density and two texture attributes (hardness 1, springiness) could be well predicted (R² > 0.98) from tryptophan and NADH spectra.     

Comparison of Infrared Spectroscopy and Nuclear Magnetic Resonance Techniques in Tandem with Multivariable Selection for Rapid Determination of ω-3 Polyunsaturated Fatty Acids in Fish Oil

This study investigated the potential of using four spectroscopic techniques including visible–short-wave near infrared, long-wave near infrared (LNIR), mid-infrared, and nuclear magnetic resonance (NMR) spectroscopy in tandem with multivariable selection and calibration for rapid determination of three important ω-3 polyunsaturated fatty acids (PUFA), namely eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and docosapentaenoic acid (DPA) in fish oil. Quantitative models were established between the spectral data and reference PUFA contents of samples based on partial least squares regression (PLSR) algorithm. Successive projections algorithm (SPA) and uninformative variable elimination (UVE) were used to select the most important variables for prediction. The average decrements of 23.20 % for root mean square error of cross-validation (RMSECV) and 64.90 % for the absolute value between root mean square error of calibration and RMSECV (AV_RMSE) in all 12 cases achieved after over 90 % variables were eliminated. UVE was also found to be helpful to improve the efficiency of SPA’s variable selection in 8/12 cases. The best predictions for EPA, DHA, and DPA were all achieved by NMR spectroscopy (determination coefficients of cross-validation (r _CV ² ) of 0.970, 0.982, and 0.983 and the RMSECV of 11.48, 4.73, and 0.77 mg/g for the EPA, DHA, and DPA predictions, respectively). LNIR spectra also did good predictions similar to NMR. The results demonstrated that the laborious and time-consuming gas chromatography method could be replaced by spectroscopic techniques in tandem with PLSR modeling and variable selection in order to provide a rapid and reliable inspection of PUFA in fish oil.     

Relationship between wine composition and temperature: Impact on Bordeaux wine typicity in the context of global warming—Review

Weather conditions throughout the year have a greater influence than other factors (such as soil and cultivars) on grapevine development and berry composition. Temperature affects gene expression and enzymatic activity of primary and secondary metabolism which determine grape ripening and wine characteristics. In the context of the climate change, temperatures will probably rise between 0.3°C and 1.7°C over the next 20 years. They are already rising and the physiology of grapevines is already changing. These modifications exert a profound shift in primary (sugar and organic acid balance) and secondary (phenolic and aromatic compounds) berry metabolisms and the resulting composition of wine. For example, some Bordeaux wines have a tendency toward reduced freshness and a modification of their ruby color. In this context it is necessary to understand the impact of higher temperatures on grape development, harvest procedures, and wine composition in order to preserve the typicity of the wines and to adapt winemaking processes.     

Simultaneous Determination of Biogenic Amines and Methylxanthines in Foodstuff—Sample Preparation with HPLC-DAD-FL Analysis

Chromatographic system for simultaneous determination of levodopa, biogenic amines, and methylxanthines in food has been developed. Chromatographic column and pre-column with octadecylsilane phase and simultaneously fluorescence and DAD detectors have been used. Gradient elution with acetate buffer (pH?=?4.66) with acetonitrile has been applied. Examination included levodopa, norepinephrine, dopamine, normetanephrine, tyramine, and serotonin as well as caffeine, theophylline, and theobromine. Limit of detection (LOD) and limit of quantitation (LOQ) have been determined for all compounds with signal to noise ratio (S/N) equal to 3 and 10, respectively. LOD of 10 ng/mL and LOQ of 30 ng/mL for levodopa and biogenic amines as well as LOD of 70 (60)?ng/mL and LOQ of 210 (180)?ng/mL for methylxanthines have been determined. Authors have also developed method for simultaneous separation of all analytes from food matrix. Developed chromatographic system with sample preparation method has been applied for determination of examined compounds in cocoa products, vegetables, and fruits.     

Effects of Vacuum Packaging and Wrapping with Chitosan-Based Edible Film on the Extension of the Shelf Life of Sea Bass (Dicentrarchus labrax) Fillets in Cold Storage (4 °C)

In the present study, we assessed the possibility of improving the shelf life of fresh sea bass (Dicentrarchus labrax) fillets by using vacuum packaging and wrapping with chitosan-based edible films during cold storage at 4 °C. Sea bass fillet samples were periodically evaluated to assess chemical (pH, trimethylamine and total volatile basic nitrogen) and microbiological (presence of mesophilic aerobic bacteria and psychrotrophic bacteria) quality. Chemical spoilage (trimethylamine and total volatile basic nitrogen) and growth of microorganisms (total mesophilic and total psychrophilic aerobic bacterial counts) were significantly reduced (P?≤?0.05) in vacuum-packaged chitosan film wrapping during cold storage at 4 °C. The results showed that the shelf life of the control and vacuum-packaged groups ended within 5 days, whereas that of vacuum-packaged chitosan film-wrapped samples ended at 25 to 30 days. Therefore, the shelf life of sea bass fillets wrapped in chitosan was prolonged by about 20 days.     

The Use of Molecular Methods for Detecting and Discriminating Salmonella Associated with Foods — A Review

The genus Salmonella is composed of two species, Salmonella enterica and Salmonella bongori. Only S. enterica subsp. enterica is considered of human clinical significance and consists of 1478 serotypes. A large number of virulence genes and virulence-enhancing genes have been described for Salmonella. There are more than 30 Salmonella specific genes that have been used for the polymerase chain reaction to detect and characterize Salmonella. The sensitivity of detection of Salmonella from complex matrices such as food and feces by PCR is invariably enhanced using nonselective or selective enrichment, particularly if followed by immuno-magnetic separation in addition to coupling the PCR with ELISA formats. R-plasmids are considered to be the main factors responsible for the horizontal transfer of antibiotic resistance genes in Salmonella. A sizeable number of primer pairs are available for determining by the PCR the presence of many antibiotic resistance genes in Salmonella isolates that are not necessarily specific for Salmonella. The collective PCR detection of members of the genus Salmonella in foods and environmental samples has been achieved by amplification of invA gene sequences that are highly conserved among all Salmonella serotypes in addition to the amplification of his gene sequences also present throughout the genus Salmonella. Amplification of 16S rDNA sequences have also been found useful for genus specific detection of Salmonella. d-Tartrate (dT⁺) fermenting strains have been found to result in less severe gastrointestinal infections than d-tartrate-nonfermenting (dT^-) strains. Primers have therefore been developed for distinguishing between (dT⁺) and (dT^-) strains. Among the molecular techniques available for strain discrimination of Salmonella isolates, pulsed field gel electrophoresis, random amplified polymporphic DNA analysis, ribotyping, multilocus sequence typing, subtracted finger printing, and enterobacterial repetitive intergeneric consensus typing have been found useful. Multiplex PCR has been found effective for simultaneously detecting Salmonella and other pathogens in foods, particularly with real-time PCR.     

Combined industrial processes with irradiation to assure innocuity and preservation of food products — a review

The desire to assure food safety for consumption requires better food preservation techniques. The presence of parasites, insects, mites, and micro-organisms, is an important source of problems. In this regard, irradiation is an interesting alternative to be considered to satisfy quarantine requirements, to control severe losses during transportation and commercialization, and to insure food safety. This paper reviews some potential applications of irradiation for preserving food products.     

Use of micellar casein concentrate and milk protein concentrate treated with transglutaminase in imitation cheese products—Melt and stretch properties

Melt and stretch properties in dairy-based imitation mozzarella cheese (IMC) are affected by the amount of intact casein provided by dairy ingredients in the formulation. Rennet casein (RCN) is the preferred ingredient to provide intact casein in a formulation. Ingredients produced using membrane technology, such as milk protein concentrate (MPC) and micellar casein concentrate (MCC), are unable to provide the required functionality. However, the use of transglutaminase (TGase) has potential to modify the physical properties of MPC or MCC and may improve their functionality in IMC. The objective of this study was to determine the effect of TGase-treated MPC and MCC retentates on melt and stretch properties when they are used in IMC and to compare them with IMC made using RCN. The MCC and MPC retentates were produced using 3 different lots of pasteurized skim milk and treated with 3 levels of TGase enzyme: no TGase (control), low TGase: 0.3 units/g of protein, and high TGase: 3.0 units/g of protein. Each of the MCC and MPC treatments was heated to 72°C for 10 min to inactivate TGase and then spray dried. Each MCC, MPC, and RCN powder was then used in an IMC formulation that was standardized to 48% moisture, 21% fat, 20% protein, and 1% salt. The IMC were manufactured in a twin-screw cooker by blending, mixing, and heating various ingredients (4.0 kg). Due to extensive crosslinking, the IMC formulation with the highest TGase level (MCC or MPC) did not form an emulsion. The IMC made from MCC treatments had significantly higher stretchability on pizza compared with their respective MPC treatments. The IMC made from TGase-treated MCC and MPC had significantly lower melt area and significantly higher transition temperature (TT) and stretchability compared with their respective controls. Comparison of IMC made using TGase-treated MCC and MPC to the RCN IMC indicated no difference in TT or texture profile analysis-stretchability; however, the Schreiber melt test area was significantly lower. Our results demonstrated that TGase treatment modifies the melt and stretch characteristics of MCC and MPC in IMC applications, and TGase-treated MPC and MCC can be used to replace RCN in IMC formulations.     

Use of micellar casein concentrate and milk protein concentrate treated with transglutaminase in imitation cheese products—Unmelted texture

The amount of intact casein provided by dairy ingredients is a critical parameter in dairy-based imitation mozzarella cheese (IMC) formulation because it has a significant effect on unmelted textural parameters such as hardness. From a functionality perspective, rennet casein (RCN) is the preferred ingredient. Milk protein concentrate (MPC) and micellar casein concentrate (MCC) cannot provide the required functionality due to the higher steric stability of casein micelle. However, the use of transglutaminase (TGase) has the potential to modify the surface properties of MPC and MCC and may improve their functionality in IMC. The objective of this study was to determine the effect of TGase-treated MPC and MCC powders on the unmelted textural properties of IMC and compare them with IMC made using commercially available RCN. Additionally, we studied the degree of crosslinking by TGase in MPC and MCC retentates using capillary gel electrophoresis. Three lots of MCC and MPC retentate were produced from pasteurized skim milk via microfiltration and ultrafiltration, respectively, and randomly assigned to 1 of 3 treatments: no TGase (control); low TGase: 0.3 units/g of protein; and high TGase: 3.0 units/g of protein, followed by inactivation of enzyme (72°C for 10 min), and spray drying. Each MCC, MPC, and RCN was then used to formulate IMC that was standardized to 21% fat, 1% salt, 48% moisture, and 20% protein. The IMC were manufactured by blending, mixing, and heating ingredients (4.0 kg) in a twin-screw cooker. The capillary gel electrophoresis analysis showed extensive inter- and intramolecular crosslinking. The IMC formulation using the highest TGase level in MCC or MPC did not form an emulsion because of extensive crosslinking. In MPC with a high level of TGase, whey protein and casein crosslinking were observed. In contrast, crosslinking and hydrolysis of proteins were observed in MCC. The IMC made from MCC powder had significantly higher texture profile analysis hardness compared with the corresponding MPC powder. Further, many-to-one (multiple) comparisons using the Dunnett test showed no significant differences between IMC made using RCN and treatment powders in hardness. Our results demonstrated that TGase treatment causes crosslinking hydrolysis of MCC and MPC at higher TGase levels, and MPC and MCC have the potential to be used as ingredients in IMC applications.     

Transition cow nutrition and management strategies of dairy herds in the northeastern United States: Part II—Associations of metabolic- and inflammation-related analytes with health,milk yield,and reproduction

The objectives were as follows: (1) establish cow-level thresholds for prepartum nonesterified fatty acids (NEFA) and postpartum NEFA, β-hydroxybutyrate (BHB), and haptoglobin (Hp) concentrations associated with negative health events; (2) evaluate cow-level associations between biomarkers and 305-d mature equivalent milk at the fourth test day (ME305) and reproductive performance; and (3) identify herd-alarm levels (proportion of cows sampled above the critical threshold) for biomarkers that are associated with herd-level changes in disorder incidence (displaced abomasum and clinical ketosis), reproductive performance, and ME305. In a prospective cohort study, 1,473 cows from 72 farms were enrolled from the northeastern United States. Blood samples were collected from the same 11 to 24 cows per herd during the late-prepartum and early-postpartum periods. Whole blood was analyzed for postpartum BHB concentrations; plasma was analyzed for prepartum and postpartum NEFA and postpartum Hp concentrations. Critical thresholds for the biomarkers associated with health events for all cows were established using a receiver operating characteristic curve analysis. Poisson, linear mixed effects, and Cox proportional hazards models investigated the association of the biomarkers with health and performance. The prepartum NEFA and Hp threshold associated with culling was ≥0.17 mmol/L and 0.45 g/L, respectively. The postpartum NEFA and BHB thresholds associated with diagnosis of metritis, displaced abomasum, or clinical ketosis were ≥0.46 mmol/L and ≥0.9 mmol/L, respectively. Multiparous cows with prepartum NEFA concentration ≥0.17 mmol/L produced 479 kg less ME305. Multiparous and primiparous cows with postpartum NEFA concentration ≥0.46 mmol/L produced 280 kg less and 446 kg more ME305, respectively. Cows with BHB concentration ≥0.9 and ≥1.1 mmol/L produced 552 kg more ME305 and had a 20% decreased risk of pregnancy within 150 d in milk, respectively; however, multiparous cows with BHB concentration ≥1.5 mmol/L produced 376 kg less ME305. Cows with Hp concentration ≥0.45 g/L produced 492 kg less ME305 and had 28% decreased risk of pregnancy within 150 DIM. Cows with Hp concentration ≥0.45 g/L had 19% decreased pregnancy risk to first service (PRFS). Herds above the herd-alarm levels for prepartum NEFA had a 6.0-percentage unit increase in disorder incidence and a 6.0-percentage unit decrease in 21-d pregnancy rate (PR) for multiparous cows, a 3.9-percentage unit increase in PR and a 5.8-percentage unit increase in the probability of pregnancy for primiparous cows. Herds above the herd-alarm levels for postpartum NEFA had a 5.8- and 4.2-percentage unit increase in disorder incidence for multiparous and primiparous cows, respectively, a 789 kg decrease in ME305 for multiparous cows, and a 6.8- and 6.3-percentage unit decrease and increase in PR and PRFS for multiparous cows, respectively. Herds above the herd-alarm levels for BHB had an 8.5-percentage unit increase in disorder incidence, a 332 and 229 kg increase in ME305 for primiparous and multiparous cows, respectively, and a 3.2-, 5.2-, and 7.0-percentage unit decrease in PR, probability of pregnancy, and PRFS, respectively. Herds above the herd-alarm levels for postpartum Hp had a 5.3-percentage unit increase in disorder incidence. At the cow level and herd level, elevated biomarker concentrations were associated with an increased disorder risk and varied performance responses.     

How do dairy cows chew?—Particle size analysis of selected feeds with different particle length distributions and of respective ingested bolus particles

Not only feed but also respective bolus particle size could alter diet efficiency and cow performance. The objective of this project was to characterize particle size of selected feeds and respective swallowed boli. Feed samples included 6 different particle length rye grass hay samples, 1 grass silage, 1 corn silage, and 1 total mixed ration (TMR). Rye grass hay samples consisted of long hay and chopped hay particles retained on the 19- (19_PSPS hay), 8- (8_PSPS hay), and 1.18-mm (1.18_PSPS hay) Penn State Particle Separator (PSPS) screens and those collected on the pan (PSPS_pan hay). A sixth hay treatment was rye grass forage cut at 50-mm lengths and dried to hay (50-mm hay). Treatments were offered to 4 nonlactating and 4 lactating cows following rumen evacuation. Swallowed boli were collected and the number of chews per gram of ingested feed dry matter was determined. Feed and bolus particles of lengths ≥5mm were collected on a 1.6-mm screen using a horizontal wet sieving technique. This cut point was chosen, as the literature suggests that most fecal particles are shorter than 5mm. Dry matter proportions on this screen (PROP_1.6) were determined and particle lengths of retained particles were measured by image analysis. Mean particle lengths (ML) were calculated considering particles ≥5mm in length. Boli of long hay, of 19_PSPS hay, of 8_PSPS hay, and of 50-mm hay had similar ML of 10 to 11mm. Bolus PROP_1.6 were also similar between these treatments, ranging from 0.54 to 0.69. Bolus particle lengths and distributions of these treatments were not related to respective hay particles. Bolus of 1.18_PSPS hay had PROP_1.6 of 0.51 and a smaller ML of 8mm. The PSPS_pan hay had PROP_1.6 of only 0.33, but was still chewed intensely. Apparently, little particle size reduction occurred when cows ate the TMR or the silages. Feed and respective bolus PROP_1.6 were as follows: 0.66 and 0.59 in grass silage, 0.52 and 0.55 in corn silage, and 0.44 and 0.38 in the TMR. Feed and respective bolus ML were as follows: 13.8 and 11.6mm in grass silage, 12.0 and 11.2mm in corn silage, and 13.1 and 12.5mm in the TMR. Rye grass hay particles retained on PSPS screens ≥8mm, with ML of at least 25mm were longer compared with TMR particles, but respective bolus particles were shorter. Bolus particle size is not associated with the size of large feed particles chewed to a constant size that is appropriate for deglutition. This size may be related to feed chemical composition.