Oxidation of ascorbic acid with hydrogen peroxide: investigation with a reaction calorimeter

The oxidation of ascorbic acid (AA) implies first the formation of dehydro-ascorbic acid (DHA) and, in a second step, a further oxidation that breaks the molecule in smaller mass compounds, like oxalic acid and 1,2-ethandiol-1,2-dicarboxy acid. The overall process is therefore the result of two consecutive steps. The process was investigated in isothermal conditions with a reaction calorimeter at different concentration, pH and temperatures. The instrument used is a chemical process analyser CPA202 developed by ChemiSense\uae and designed to suppress uncontrolled temperature differences between the content of the reactor and its. This means that all the heat exchanged from the reactor to the thermostat bath flows through the heat transducer, which is located between the bottom of the reactor and a Peltier element used as a heat pump. A two consecutive step kinetic model allows fitting the experimental trends, provided that a damping factor, exp(-\uf074\uf02ft), is introduced to account for the delay of heat transfer (about 100 s). Both steps follow a first order kinetics (although other combinations were also considered). Taking into account that the overall thermal effect is exothermic, the reaction enthalpies were assumed both negative, or one positive and the other negative

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

[EN] 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).Authors are thankful to the Province of Bolzano for financial support (Landesregierung mittels Beschluss Nr. 1472, 07.10.2013) and also the Research Institute for Food Research and Development at the Universitat Politecnica de Valencia (UPV), for laboratory facilities.Armellini, R.; Peinado Pardo, I.; Pittia, P.; Scampicchio, M.; Heredia Gutiérrez, AB.; Andrés Grau, AM. (2018). Effect of saffron (Crocus sativus L.) enrichment on antioxidant and sensorial properties of wheat flour pasta. Food Chemistry. 254:55-63. https://doi.org/10.1016/j.foodchem.2018.01.174S556325

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

[EN] 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¿±¿1.1, to 97¿±¿3%. Finally, the trans:cis isomers distribution was only close to 50:50 in enriched-pasta cooked during 3¿min or with oil addition.Authors are thankful the Province of Bolzano for financial support (Landesregierung mittels Beschluss Nr. 1472, 07.10.2013) and also the Research Institute for Food Research and Development at the Universitat Politecnica de Valencia (UPV), for laboratory facilities.Armellini, R.; Peinado, I.; Asensio-Grau, A.; Pittia, P.; Scampicchio, M.; Heredia Gutiérrez, AB.; Andrés Grau, AM. (2019). In vitro starch digestibility and fate of crocins in pasta enriched with saffron extract. Food Chemistry. 283:155-163. https://doi.org/10.1016/j.foodchem.2019.01.041S15516328

Structured Vegetable Lipids as Ice Cream Fat Source

This research aimed to develop a low-saturated ingredient as substitute of saturated fats by structuring lipids through a simple enzymatic glycerolysis process. To this purpose, peanut oil (10 g) was mixed with glycerol (1:1 molar ratio) and lipase (0.4 g). The glycerolysis reaction was carried out for 16 h at 65°C under constant stirring. The obtained structured lipid was then used as a fat source in a mixture for the production of ice cream. The mixtures obtained with structured and unstructured peanut oil were compared to a classical cream-based mixture in terms of particle size and ?-potential. Afterward, the obtained ice creams were assessed based on their physical properties during melting and textural attributes. Glycerolysis of peanut oil reduced the particle size of the formed mixtures, which later created ice creams with a slower melting rate (0.044 g·min-1) compared to the peanut oil-based formulation (0.77 g·min-1). Similar dripping times were measured for the structured-lipid (60.33 ± 1.2 min) and the cream-based (65.00 ± 1.6 min) ice creams. Moreover, the firmness and consistency of the ice cream made with the structured lipid were not significantly different (p < 0.05) compared to the traditional cream-based product. Overall, the results of the present study clearly indicated that structured lipids could be used as ingredient in ice cream production, paving the way for a partial replacement of saturated fats in food formulations

Nanotechnology and Food Quality Control

The preparation and attractive performance of nanomaterials for innovative detection schemes of food related compounds are described. Nickel nanowires growths by the template procedure were used for magnetoswitchable control of electrochemical processes of sugar-like compounds at the electrode surface. Gold nanoparticles were also prepared by reducing a gold solution with different phenolic compounds. The different antioxidant power of these compounds allow to modulate the kinetic growth of gold nanoparticles. Finally, an index of the antioxidant power based on the growth of gold nanoparticle is reported

Proton transfer reaction-mass spectrometry (PTR-MS) for rapid detection of oxidised odour in milk during storage

Milk flavour varies greatly depending on its oxidation state, which can be measured by several methods like HPLC or GC-MS. However, due to constraints associated with methodological complexity, time of analysis and costs, implementation of these methods in food industry is often limited. Recently, proton transfer reaction-mass spectrometry (PTR- MS) has been proposed as an alternative analytical technique, especially for food quality control. PTR-MS offers advantages over some traditional methods including the involvement of a mass spectrometer based on soft ionisation. This means that the resulting mass signals are mainly composed of protonated parent ions derived from volatile organic compounds (allowing their straightforward interpretation). Moreover, PTR-MS allows direct and continuous measurement and suitable for rapid on-line monitoring of foods during processing or storage. Therefore, PTR-MS was used here for rapid detection of milk oxidation. Oxidation state was determined by measuring hexanal, a well-known marker of fat oxidation in milk samples. Hexanal was monitored by tracking the changes in the abundance of the mass fragment at m/z 83. Different oxidation states in milk samples were induced by spiking different concentrations of Cu++ (i.e. increasing from 0 to 32 ppm) during storage conditions (4\ub0C). Results showed that the intensity of the mass fragment at m/z 83 evolved following a sigmoidal trend with a maximum rate proportional to the Cu++ content in milk. The proposed analysis procedure is fast, sensitive (8.8 \ub1ppbv/\ub5M), precise (RSD < 6%; low limit of detection: 0.5 \ub5M), and non-invasive. Therefore, this PTR-MS procedure is suitable for rapid detection of hexanal to monitor the oxidative changes in milk. Keywords: milk oxidation, copper, hexanal, rapid method