Role of saccharides on thermal stability of phycocyanin in aqueous solutions.

The effect of heat and equivalent thermal effect ( [Formula: see text] ) on discolouration of Spirulina algae extracts in water, sucrose and trehalose solutions at different concentration was investigated and kinetics of phycocyanin degradation evaluated by spectrophotometric and circular dichroism. At constant temperature, colour loss increased at increasing time and decreased at increasing solute concentration. Circular dichroism confirmed relation between colour loss and protein structure destabilization, and the thermostabilising effect of saccharides with sucrose performing better than trehalose. Apparent constant rate values determined by the Weibullian probabilistic model describe the corresponding phycocyanin degradation kinetics; a linear correlation between the activation energy and aw of the solutions has been found. Origin of phycocyanin and system saccharide concentration resulted significant discriminant factors on the discolouration when [Formula: see text] was taken into account. Results may find application in product formulation and processing optimisation, thereby the use of Spirulina extracts as colouring foodstuff could be enhanced.

In vitro starch digestibility and fate of crocins in pasta enriched with saffron extract.

This work aims to study the effect of the addition of saffron extract on fresh pasta in-vitro digestibility. Fresh pasta was formulated with different concentrations of saffron extracts (0.2 and 0.4 %w/w), cooked at two different times (1.5 and 3 min), and in vitro digested (oral, gastric and intestinal stages). Oil was added to pasta before digestion to evaluate the presence of lipids on starch and crocin bioaccessibility. Saffron enrichment and oil addition slowed down the digestion of starch, thus, decreasing the glycemic index of pasta. Concentration of saffron and oil addition contributed to crocin release in the digestion fluids, with the opposite effect of cooking time. Isomerization from trans to cis was enhanced by both, cooking and oil addition. Bioaccessibility of total crocins varied from 2.9 ±â€¯1.1, to 97 ±â€¯3%. Finally, the trans:cis isomers distribution was only close to 50:50 in enriched-pasta cooked during 3 min or with oil addition.

Crocins pattern in saffron detected by UHPLC-MS/MS as marker of quality, process and traceability.

This study was carried out to develop an UHPLC-MS/MS analytical procedure, to determinate all isomers and isoforms of crocins of 42 saffron samples, with different origin, age and dried using different process conditions. A preliminary experimental design was applied to optimize the extraction of crocins; UHPLC-MS/MS conditions were set to obtain the best analytical performances in terms of sensitivity and selectivity. The optimised conditions allowed to determine ten crocins; their amount in samples was significantly different and affected by process, age and origin. Drying conditions influenced the crocins pattern and this was particularly evidenced in the more recently produced samples, with a clear separation between mild and high thermally treated samples. Principal Component Analysis of all crocins data allowed to discriminate samples based on origin (Italy vs. other countries) and age. Results confirm the feasibility of the use of crocins pattern as marker of quality and traceability of saffron.

Effect of saffron (Crocus sativus L.) enrichment on antioxidant and sensorial properties of wheat flour pasta.

Saffron, used in cookery as a flavouring and colouring agent, is well-known for its antioxidant and beneficial health properties. In the present work, the effect of saffron addition (0-control, 0.1, 0.2 and 0.4%, w/w) in the formulation of fresh pasta was evaluated on textural, physical-chemical, and sensory properties of the cooked product. Content and retention of the bioactive molecules of saffron (crocins) were evaluated by HPLC along with the corresponding antioxidant activity of enriched pasta. The presence of saffron significantly influenced textural and physical-chemical properties of pasta. Higher saffron concentrations enhanced the antioxidant activity of pasta with the higher values of crocins in samples enriched with 0.4% saffron extract even after 3 min of cooking (4.23-5.06 mg/g db). Sensory analysis showed an increased acceptability of the saffron enriched pasta for all descriptors selected (visual aspect, colour, aroma, taste, chewiness, hardness, gumminess and overall acceptability).

Gold nanoparticles-peptide based gas sensor arrays for the detection of food aromas.

A gas sensor array based on peptide modified gold nanoparticles deposited onto 20MHz quartz crystal microbalances has been realized. Glutathione and its constituting aminoacids and dipeptides have been used as ligands. A great increase in sensitivity (2 orders of magnitude) was achieved using gold nanoparticles versus monolayer modified QCMs. The sensors have been characterised in terms of sensitivity for hexane, water, trimethylammine and ethanol. Highest sensitivity was found for water. The ability to discriminate typical food aromas as cis-3-hexenol, isopentylacetate, ethylacetate, and terpinen-4-ol dissolved in different solvents was studied using a gas sensor array constituted by gold nanoparticles modified with the glutathione peptides, thioglycolic acid and an heptapeptide. The array was found able to discriminate the food aromas, the response being dependent on the polarity of the solvent used. Tests on real olive oil samples gave a satisfactory separation among samples having defects versus non defected samples demonstrating that this approach has high potential for the development of gas sensor arrays to be used in real samples.

Effect of sugars on liquid-vapour partition of volatile compounds in ready-to-drink coffee beverages.

The effect of sugars (sucrose, lactose, glucose, fructose, 10%w/v) on the liquid-vapour partition of selected volatile compounds of coffee beverages has been investigated in espresso coffee and ready-to-drink (RTD) canned coffee prepared and obtained by using the same Arabica roasted coffee beans blend. Aroma composition of coffee beverages has been preliminary investigated by headspace-gas chromatography (HS-GC) and solid phase microextraction-HS-GC-mass spectrometry to characterize the volatile pattern of the systems and to evaluate the effects of sugars on the aroma release/retention. Then, the liquid-vapour partition coefficient (k) of 4 selected key aroma compounds (diacetyl, 2,3-pentanedione, ethylpyrazine, hexanal) was determined in water, sugars solutions as well as RTD coffee brews added with the same sugars (10%w/v). Sugars added in coffee beverages affected the release of the volatiles and thus its aroma profile with differences due to the type of added sugar and coffee brew type. The k values of the selected volatile compounds resulted different depending on the model system composition (water, coffee brew) and sugar type added. In particular, melanoidins as well as other non-volatile components (lipids, acids, carbohydrates) in the RTD coffee brews could be implied in the change of k of the volatile compounds in respect to that observed in water. The effects of the sugar type on the release/retention of the four key coffee aroma compounds were partly explained in terms of 'salting out' especially for the more polar volatile compounds and in the sucrose-added model systems. The change of chemical and physico-chemical properties of the water and brews induced by the sugars as well as the occurrence of interactions between volatile compounds and non-volatile components may be implied in the reduction of the vapour partition of the aroma compounds.

Meat quality in male fallow deer (Dama dama): effects of age and supplementary feeding.

Thirty-two male fallow deer, half 18- and half 30-month-old, were slaughtered after a 4-month feeding trial on pasture alone or with daily supplement of 500 g (dry matter) concentrate/head (eight each 18- and 30-month-old). Neither diet nor age produced significant effects on M. longissimus thoracis et lumborum (LM) and on M. semimembranosus (SM) pH and colour. Meat texture properties (Warner-Bratzler-WB Shear Force and compression), water loss and collagen content were unaffected by diet, while the older deer had higher LM WB peak force values (4.15 vs 4.88 kg) and lower collagen solubility (34.61 vs 22.58%). LM and M. semitendinosus (ST) of the supplemented deer had a higher content of fat (pasture vs concentrate feeding: 0.56 vs 0.72% in LM; 0.55 vs 0.78% in ST) and provided lower PUFA, particularly n-3 PUFA, and higher n-6/n-3 ratio (3.30 vs 4.76 in LM; 3.39 vs 4.63 in ST). Thirty-month-olds' LM and ST were fatter than 18-month-olds', and provided lower PUFA, both in the n-6 and n-3 fraction.

Characterization of high-pressure-treated egg albumen.

Addition of NaCl or sucrose to egg albumen prior to high-pressure treatment (up to 10 min at 800 MPa) prevented insolubilization or gel formation after pressure treatment. As a consequence of protein unfolding, the treated albumen had increased viscosity but retained its foaming and heat-gelling properties. Susceptibility of egg albumen proteins to hydrolysis by trypsin increased dramatically after pressure treatment. The S-form of ovalbumin, the presence of which is an index of egg aging, was not found in any of the pressure-treated samples, which also did not display evidence for covalent protein aggregation. However, recognition of ovalbumin by an anti-ovalbumin antiserum was reduced to 40% of that of untreated sample.