Rapid and non-destructive analysis of apricot fruit quality using FT-near-infrared spectroscopy

A non-destructive optical method based on near-infrared spectroscopy has been used for the evaluation of apricot fruit quality. Diffuse reflectance measurements (800–2500 nm), physical, physiological and biochemical measurements were performed individually on 877 apricot fruits from eight contrasted cultivars harvested at different ripening stages. Relationships between spectral wavelengths and quality attributes were evaluated by application of chemometric techniques based on partial least squares (PLS) on fruit set divided randomly into two groups: 598 fruits for calibration and 279 for validation. Good prediction performance was obtained for soluble solids and titratable acidity with correlation coefficients of 0.92 and 0.89 respectively and root mean square errors of prediction of 0.98% Brix and 3.62 meq 100 g⁻¹ FW respectively. For the other quality traits such as firmness, ethylene, individual sugars and organic acids, the prediction models were not satisfactorily accurate due to the high error of calibration and prediction.     

Psychostimulants and children: A review and analysis.

Effects of psychostimulant medication for children are reviewed in 3 areas: motor activity, attention and cognition, and social-adaptive behavior. Prevailing misconceptions about these drugs and the children who take them are examined, as are the disparities between findings on short- and long-term effects. The dearth of knowledge and theory regarding psychological concomitants of stimulant medication is noted, and a sociocognitive analysis of drug effects is proposed. Recent research on causal attributions is reviewed, and a set of hypotheses and research strategies is developed, centering on the proposition that stimulant medication is a powerful source of attributional change in both the child and others. A major conclusion is that predicting and enhancing medication effects may depend on understanding and modifying the social and cognitive sequelae of drug intervention. A further suggestion is that the prevalence and import of psychoactive drug use make this a fruitful area for testing attribution and expectancy theories. (31/2 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Death of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in shelf-stable, dairy-based, pourable salad dressings

The objectives of this study were to determine the death rates of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in three commercially manufactured full-fat ranch salad dressings, three reduced-fat ranch salad dressings, two full-fat blue cheese salad dressings, and two reduced-fat blue cheese salad dressings and to affirm the expectation that these dressings do not support the growth of these pathogens. The respective initial pH values of the four types of shelf-stable, dairy-based, pourable dressings were 2.87 to 3.72, 2.82 to 3.19, 3.08 to 3.87, and 2.83 to 3.49, respectively. Dressings were inoculated with low (2.4 to 2.5 log CFU/g) and high (5.3 to 5.9 log CFU/g) populations of separate five-strain mixtures of each pathogen and stored at 25 degrees C for up to 15 days. Regardless of the initial inoculum population, all test pathogens rapidly died in all salad dressings. Salmonella was undetectable by enrichment (<1 CFU/25-ml sample in three replicate trials) in all salad dressings within 1 day, and E. coli O157:H7 and L. monocytogenes were reduced to undetectable levels by enrichment between 1 and 8 days and 2 and 8 days, respectively. E. coli O157:H7 was not detected in 4 of the 10 salad dressings stored for 2 or more days and 9 of the 10 dressings stored for 6 or more days after inoculation. L. monocytogenes was detected in 9 of the 10 salad dressings stored for 3 days but in only one dressing, by enrichment, at 6 days, indicating that it had the highest tolerance among the three pathogens to the acidic environment imposed by the dressings. Overall, the type of dressing (i.e., ranch versus blue cheese) and level of fat in the dressings did not have a marked effect on the rate of inactivation of pathogens. Total counts and populations of lactic acid bacteria and yeasts and molds remained low or undetectable (<1.0 log CFU/ml) throughout the 15-day storage period. Based on these observations, shelf-stable, dairy-based, pourable ranch and blue cheese salad dressings manufactured by three companies and stored at 25 degrees C do not support the growth of Salmonella, E. coli O157:H7, and L. monocytogenes and should not be considered as potentially hazardous foods (time-temperature control for safety foods) as defined by the U.S. Food and Drug Administration Food Code.     

Profile of fatty acids, muscle structure and shear force of musculus longissimus dorsi (MLD) in growing pigs as affected by energy and protein or protein restriction followed by realimentation

Forty-eight gilts were submitted to a 30% restriction of feed (groups F and F1) or protein intake (group P) from 90 to 118 days of age, followed by realimentation from 119 to 168 days of age. Control pigs (C) were fed during the whole experiment according to a semi ad libitum scale. During realimentation all animals were fed according to semi ad libitum scale except pigs F1 which were fed ad libitum. Six pigs from each group were slaughtered at the end of restriction and realimentation. Restriction decreased the weight of musculus longissimus dorsi (MLD) and increased shear force. Restriction of feed intake depressed MUFA concentration and increased n-6/n-3 ratio while protein restriction decreased n-6/n-3 and PUFA:SFA ratios. Structure of fibers was not affected. After realimentation MLD mass was still lower in all previously restricted pigs, shear force was the lowest in F1 pigs. Only percentage of fast twich oxidative fibers was significantly greater in F1 pigs than in others. Significant correlations between parameters investigated during the study were found.     

Hydrostatic pressure effects on the structural properties of condensed whey protein/lactose systems

Hydrostatic pressure effects on whey protein/lactose mixtures were recorded with subsequent analysis of their structural, molecular and glass transition properties in comparison to thermal effects at atmospheric pressure. Experimental techniques used were small deformation dynamic oscillation in shear, modulated differential scanning calorimetry, Fourier transform infrared spectroscopy, and theoretical modelling of glass transition phenomena. Levels of solids ranged from 30 to 80% (w/w) in formulations with a protein/co-solute ratio of four-to-one. Addition of lactose protects the secondary conformation of the protein under application of high hydrostatic pressure. Nevertheless, pressurized protein systems are able to form three-dimensional structures due to the reduction in polymeric free volume and the development of an efficient friction coefficient amongst tightly packed particles. Systems can be seen as developing a “molten globular state”, where the structural knots of pressure-treated networks remain in the native conformation but achieve intermolecular cross-linking owing to frictional contact. Furthermore, pressure treated assemblies of condensed whey protein preparations could match the viscoelasticity of the thermally treated counterparts upon cooling below ambient temperatures. That allowed examination of the physical state and morphology of a condensed preparation at 80% solids by the combined framework of reduced variables and free volume theory thus affording derivation of glass transition temperatures for pressurized and atmospheric samples.     

The influence of protein–flavonoid interactions on protein digestibility in vitro and the antioxidant quality of breads enriched with onion skin

Different types of breads enriched with onion skin were studied. The objectives were twofold: to show and examine protein–phenolic interactions and to discuss results concerning phenolic content, antioxidant activity and protein digestibility in the light of in vitro bioaccessibility. Phenolic contents and antiradical abilities were linked with the level of onion skin supplement however, the amounts determined were significantly lower than expected. Fortification influenced protein digestibility (a reduction from 78.4% for control breads to 55% for breads with a 4% supplement). Electrophoretic and chromatographic studies showed the presence of indigestible protein–flavonoid complexes – with molecular weights about 25 kDa and 14.5 kDa; however, the reduction of free amino group levels and the increase in chromatogram areas suggest that flavonoids also bind to other bread proteins. The interaction of phenolics with proteins affects antioxidant efficacy and protein digestibility; thus, they have multiple effects on food quality and pro-health properties.     

Use of Hydrolysates from Yellowfin Tuna (Thunnus albacares) Heads as a Complex Nitrogen Source for Lactic Acid Bacteria

Two different peptones obtained by enzymatic hydrolysis of yellowfin tuna (Thunnus albacares) head waste have been shown to be effective in promoting the growth of lactic acid bacteria (Lactobacillus bulgaricus Persian Type Culture Collection (PTCC) 1332, Lactobacillus acidophilus PTCC 1643, Lactobacillus casei PTCC 1608, Lactobacillus delbrukii PTCC 1333, Lactobacillus plantarum PTCC 1058, Lactococcus lactis PTCC 1336, and Lactobacillus sakei PTCC 1712). Peptones obtained from the enzymatic hydrolysis with Alcalase or Protamex were used instead of the standard peptones used in commercial MRS media. Peptones produced by Alcalase and Protamex had a 34% and 19% degree of hydrolysis, respectively. The results showed that the peptones from Alcalase and Protamex were better at promoting lactic acid bacteria (LAB) growth than the commercial MRS media (P < 0.05). The choice of proteolytic enzyme used to produce the fish hydrolysate had a considerable impact on the performance of the resulting hydrolysate, both in terms of maximum growth rate and biomass production. Peptones produced using Alcalase, with a higher degree of hydrolysis, induced better growth and performed better overall as an LAB substrate than those using Protamex. Current study revealed that enzymatic-modified fish by-products can be used as low cast nitrogen source for bacterial growth.     

Changes of the cell surface hydrophobicity of Lactobacillus acidophilus La‐5 in response to pH,temperature and inulin

The main topic of this study was to study how cell surface hydrophobicity (CSH) could change in response to pH, temperature and inulin; Lactobacillus acidophilus La‐5 was used as a model microorganism. pH, temperature, inulin and incubation time (exposure to prebiotic or incubation at pH 4.0 and 9.0) were combined through a full factorial design and a Central Composite Design; the results were analysed using a multifactorial anova (first step) and a stepwise regression (second step). Temperature and pH significantly affected CSH: an increase in the temperature determined a significant increase in CSH, whereas the correlation pH vs. CSH was negative, as an increase in pH caused a significant decrease in CSH. Inulin played a significant role, but its effect could be influenced by temperature, pH and exposure time. This study is the first approach on the effects of some environmental factors on CSH and suggests that the culturing conditions and/or the exposure to some prebiotics could modify it with positive or negative effects.     

Automated DNA preparation from maize tissues and food samples suitable for real-time PCR detection of native genes

There is an increasing need for high-throughput analyses of plants and food samples for the presence of specific DNA sequences, e.g. transgenic contaminations. We developed and optimized conditions for the automated isolation of DNA from several maize tissues and various edibles containing maize using the MagNA Pure LC system (Roche Applied Science). Our results show that the system provided is capable of isolating DNA from any tested source. Quantification of an endogenous gene by LightCycler real-time PCR revealed that the DNA is suitable in quality and quantity for multiple PCR analyses.