Non-destructive stochastic model-based detection of diet-induced alterations in fish texture

A stochastic model-based scheme detecting diet-induced textural alterations in fish muscle in an innovative, non-destructive manner is presented. The scheme operates on proven fault diagnosis principles as used in mechanical systems. It combines a cost-effective instrument setup, along with a non-destructive, vibration-like testing of fish samples and an accurate (under typical uncertainties) stochastic modeling of their response. The identified models provide key indicators indirectly related to the tested fish’s texture, itself affected by (and, thus indicative of) its dietary history. Statistical hypothesis tests perform comparisons of such key indicators from tests with fish samples of different dietary histories. The issued statistical decisions allow for reliable tracing of fish on the basis of the diet-induced textural changes, while quantifying the risk of the decision-making process. Validation tests involved samples from two distinct fish groups sharing similar dietary histories except for a supplementation of dietary taurine at 1 % level in one of them. The altered textural characteristics in taurine-supplemented fish (initially suggested by taste panel evaluation) were effectively detected via the proposed scheme. These promising results suggest the scheme’s potential as a non-destructive, cost-effective and reliable solution for fish traceability.     

Polyphenol extraction from Origanum dictamnus using low-transition temperature mixtures composed of glycerol and organic salts: Effect of organic anion carbon chain length

Novel low-transition temperature mixtures (LTTMs), composed of glycerol and sodium acetate, sodium propionate, and sodium butyrate, were synthesized with the aim to investigate the organic anion chain length effect on the performance of polyphenol extraction from the medicinal plant Origanum dictamnus. The LTTMs used as hydrogen bond donor:hydrogen bond acceptor molar ratio of 6:1 and after establishing optimal conditions of water content and liquid-to-solid ratio by response surface methodology, kinetics was performed to identify the highest efficient system. The results drawn indicated that the longer the anion chain length, the higher the requirement for water content to achieve optimal total polyphenol yield. Extractions with LTTMs comprising of sodium propionate and sodium butyrate gave virtually equal yields in total polyphenols, yet extraction with the former solvent was significantly less energy-demanding, with the activation energy being 8.77?kJ?mol^?1. Liquid chromatography-diode array-mass spectrometry analyses revealed that the extract obtained with glycerol/sodium propionate at 70?°C also displayed a richer polyphenolic profile, while the antioxidant activity of the extract was not negatively affected up to this temperature. This novel green solvent is therefore proposed as a highly efficient means of recovering bioactive polyphenols from plant material.     

Development of sodium propionate-based deep eutectic solvents for polyphenol extraction from onion solid wastes

Clean Technologies and Environmental Policy - The objective of the study presented herein was the optimisation of onion solid waste (OSW) polyphenol extraction, using sodium propionate-based deep...     

Sensory,microbiological, and chemical spoilage of cultured common sea bass (<Emphasis Type="Italic"> Dicentrarchus labrax</Emphasis>) stored in ice: a seasonal differentiation

Common sea bass ( Dicentrarchus labrax) of a Greek cage-culture origin, sampled in December and July, were stored in ice, and their sensory, microbiological and chemical spoilage patterns were studied as well as their seasonal differentiation. The sensory storage life was determined at 15 days of ice storage. The microbial population in the muscle reached levels of 10⁵ at the acceptability limit. The ATP breakdown pattern showed a quick depletion of inosine-monophosphate (IMP) in the first 8–9 days of ice storage and slower depletion thereafter. Inosine (INO) and hypoxanthine (Hx) were formed at significant quantities. TVBN and TBA, as indicators of protein breakdown and lipid oxidation, respectively, showed low and delayed increase. A seasonal effect was observed with summer fish showing higher rates of K-value increase during early spoilage, while winter fish showed higher K-values, microbial populations and TVBN at late spoilage stages.     

Comparison of wild and cultured gilthead sea bream (Sparus aurata); composition, appearance and seasonal variations

Major quality parameters, such as muscle composition, fat deposition, muscle fatty acid composition and external appearance were studied in wild and cultured gilthead sea bream. Muscle fat content and total depot fat (peritoneal and perivisceral fat) indicated a seasonal variation with minimum values observed in late spring and maximum in late summer. Gonadosomatic indices of cultured fish were lower than those found in wild specimens. Lipid content of cultured sea bream was much higher than that of wild fish. Differences were also observed in fatty acid profiles. Cultured fish were characterized by higher levels of monoenes, n-9 and 18:2n-6 fatty acids and wild fish by higher levels of saturates, 20:4n-6, n-3 fatty acids and n-3/n-6 ratios. Differences were also noted in the external appearance of fish.     

Effects of cultivation area and year on proximate composition and antinutrients in three different kabuli-type chickpea (Cicer arientinum) varieties

Three different varieties of kabuli-type chickpeas were cultivated in three different cultivation areas and for two years. An evaluation was carried out to see the effect of year, of variety and cultivation area on the nutritional value of chickpeas i.e. the proximate composition, the sugars (starch, non-starch polysaccharides, rafinose series oligosaccharides and sucrose) and tannins and phytic acid contents. The cultivation area, the cultivation year and the plant variety, as well as their interactions significantly affect the composition and the sugars contents in chickpea. High proportion of the total variation for all studied parameters explained by the main effects of variety indicates a significant heritability for them. Cultivation area was found to have a significant effect on starch contents, RSO, tannins and phytic acid. Year was found to affect fat contents, NSP and sucrose contents. Rainfall is the climate characteristic that may be responsible for these year-dependent differences.     

Lipid quality and filleting yield of reared meagre (Argyrosomus regius)

Reared meagre (Argyrosomus regius) of average weight 1278 g was evaluated for its filleting yield and fillet lipid quality. Filleting yield averaged 42.2%, while very low levels of muscle fat deposits were measured (1.06%). Analysis of lipid classes revealed a high proportion of polar lipids (48.3–59.1%) and low levels of neutral fatty acids (40.9–51.7%) when compared to corresponding values of other farmed fish species. Phosphatidyl‐choline (PC) was the dominant polar lipid (2.92 mg g^?1 muscle), while cholesterol the most abundant neutral lipid (1.68 mg g^?1 muscle). The fatty acid composition of meagre fillet generally reflects the dietary fatty acids. Among n‐3 fatty acids, eicosapentaenoic (4.58%) and docohexaenoic (15.0%) were measured to be the most abundant ones, and 18:2n‐6 (11.9%) was the most common n‐6 fatty acid. The fatty acid profiles of polar and neutral fractions differ, with monounsaturated fatty acids being predominant in the neutral and n‐3 polyunsaturates in the polar lipids. The high polar lipid contents and n‐3 fatty acids and the low atherogenic and thrombogenic indexes indicate a high quality of this species’ lipids.     

Decreased stature in gestational diabetes mellitus

Short stature has been associated with various degrees of abnormal glucose tolerance in middle-aged people, where the effects of age and metabolic control would be difficult to exclude. We chose to examine body stature in women with gestational diabetes mellitus (GDM), a prediabetic state affecting a young group of people. A sample of 2772 Greek pregnant women, referred for GDM screening was examined. After a 100-g oral glucose tolerance test, 1787 women were classified as normal (N), 300 women were found with one abnormal glucose value (OAV) and 685 women with GDM. Basal insulin resistance was calculated in 640 women by homeostasis model assessment. In addition, 51 pregnant women with pre-existing Type II (non-insulin-dependent) diabetes mellitus and 109 with pre-existing Type I (insulin-dependent) diabetes mellitus were included in the study. There was a gradual decrease in mean height (cm) as glucose intolerance became more severe: N: 161.0 +/- 6.2, OAV:160.2 +/- 6.1, GDM:158.7 +/- 6.3, Type II diabetes 158.2 +/- 7.0 (p < 0.001, analysis of variance]. Height in Type I diabetes (160.1 +/- 5.9) did not differ from the normal group. The difference in height between the normal and GDM groups remained (p < 0.001) when body weight, age, birth before or after 1960 and educational status were also taken into account. An independent correlation was also found between height and insulin resistance (n = 640) adjusted for the above mentioned variables. In conclusion, short stature appears to be associated with glucose intolerance as an independent variable, even when this intolerance is both mild and temporary. The previously unrecognised independent association of stature with basal insulin resistance merits further investigation.     

Fatty acid composition and volatile compounds of selected marine oils and meals

BACKGROUND: Although volatile compounds characterising seafood have been studied extensively, no similar data are available regarding the volatiles of raw materials used in fish feed. Therefore the aim of this study was to make an initial screening of the volatiles of various common marine raw materials used in the aquaculture feed industry. Nine commercial marine oils (German (GFO1, GFO2 and GFO3) and Norwegian (NFO) fish oils and salmon (SO1 and SO2), tuna (TO), sardine (SRDO) and shrimp (SHO) oils) and eight commercial marine meals (Peruvian (PFM1 and PFM2), Danish (DFM1 and DFM2) and prime quality (PQFM1 and PQFM2) fish meals and Antarctic krill meals (KM1 and KM2)) were analysed for their fatty acid profiles and volatile flavour compounds. The relation between fatty acids and volatiles was examined. RESULTS: The highest polyunsaturated fatty acid and eicosapentaenoic acid (20:5ω3) contents and ω3/ω6 ratio were found in NFO. The fatty acid composition of all marine meals except krill meals was found to be more variable among batches than that of marine oils. Regarding volatiles, all marine raw materials were characterised by the complete absence or negligible levels of eight‐ and nine‐carbon alcohols and carbonyls. All marine oils were found to have high 2‐ethyl furan, 2‐methylenebutyl cyclopropane, hexanal, 2,4‐octadiene and 3,5‐octadiene contents. Marine meals, unlike marine oils, were characterised by the almost complete absence of unsaturated and cyclic hydrocarbons and terpenes and very low levels of furans. CONCLUSION: Volatiles of marine meals differ from those of marine oils. Unlike fatty acids which give useful traceability information, volatiles seem to fail in this role owing to their strong variability. Copyright © 2008 Society of Chemical Industry