Cristina Anamaria Semeniuc

Thiobarbituric acid reactive substances in flavored phytosterol-enriched drinking yogurts during storage: formation and matrix interferences

The aim of this study was to evaluate the level of thiobarbituric acid reactive substances (TBARs) in flavored phytosterol-enriched drinking yogurts during storage, with particular attention to matrix interference. Two phytosterol-enriched drinking yogurts (with white vanilla-WV and blood orange-BO) were kept under controlled conditions (16xa0h light at 25xa0°C/8xa0h dark at 15xa0°C) for 64xa0h. During the TBARs assay, a yellow complex was formed. The UV–Vis spectra showed two absorption bands around 450 and 530xa0nm, respectively. In both flavored phytosterol-enriched drinking yogurts, the more intense absorption was around 450xa0nm. In conclusion, the development of TBA adducts leads to a higher overestimation of TBARs at 450xa0nm. The study of TBA reaction with some of the matrix compounds shows that propanal, pentanal, hexanal, p-anisaldehyde, and vanillin favor TBARs450 formation. Instead, acetaldehyde, nonanal, lactose, decanal, t-cinnamaldehyde, octanal, limonene, and lactic acid favor TBARs530 formation. The interference of volatile compounds in the TBARs assay is much higher in BO.

Stability of flavoured phytosterol-enriched drinking yogurts during storage as affected by different packaging materials.

BACKGROUNDnThe aim of this study was to investigate the influence of different packaging materials on storage stability of flavoured phytosterol-enriched drinking yogurts. White vanilla (WV) and blood orange (BO) phytosterol-enriched drinking yogurts conditioned in mono-layer and triple-layer co-extruded plastic bottles were stored at +6 ± 1 °C for 35 days (under alternating 12 h light and 12 h darkness) to simulate shelf-life conditions. Samples were collected at three different storage times and subjected to determination of total sterol content (TSC), peroxide value (PV) and thiobarbituric acid reactive substances (TBARs).nnnRESULTSnTSC was not significantly affected by packaging material or storage time and met the quantity declared on the label. PV was significantly influenced by yogurt type × packaging material × storage time interaction and TBARs by packaging material × storage time interaction.nnnCONCLUSIONnBetween the two packaging materials, the triple-layer plastic mini bottle with black coloured and completely opaque intermediate layer offered the best protection against lipid oxidation.

Characterization of pine bud syrup and its effect on physicochemical and sensory properties of kefir

This study aimed to develop a value-added kefir by the addition of pine bud syrup. For this purpose, different concentrations of pine bud syrup [2, 4, 6, 8, and 10% (w/w)] were added to kefir formulation after the fermentation. The pine bud syrup used for kefir fortification is rich in polyphenols and terpenes and has a high antioxidant activity. The study was designed to evaluate the influence of pine bud syrup on the physicochemical and sensory properties of kefir. The addition of pine bud syrup resulted in an increase in total solids and a decrease in fat content, proteins, and pH. The kefir sample with 10% pine bud syrup was the most appreciated by sensory panelists. Its overall acceptability score was higher (6.71 points) than regular kefir (5.57 points). The addition of 10% pine bud syrup improved the texture and consistency of regular kefir.

Chemometric Comparison and Classification of Some Essential Oils Extracted from Plants Belonging to Apiaceae and Lamiaceae Families Based on Their Chemical Composition and Biological Activities

This study is focused on the comparison and classification of parsley, lovage, basil, and thyme essential oils (EOs) based on their chemical composition, total phenolic content, antioxidant and antibacterial activities by using appropriate chemometric methods: Principal component analysis (PCA) and hierarchical cluster analysis (HCA). The results showed that parsley, lovage, and thyme EOs are rich in monoterpene hydrocarbons, but basil EO is rich in oxygenated monoterpenes and phenylpropanoids, and that both PCA and HCA separated essential oils into two main groups of which one contains two sub-groups. β-Phellandrene was the major component identified in parsley and lovage EOs, estragole was the major component in basil EO, and p-cymene was the major component in thyme EO. Thyme EO showed the highest level of total phenolics, the highest antioxidant capacity, and exhibited the stronger antibacterial activity, results that were emphasized by both chemometric methods used. Among tested essential oils, the one of parsley was distinguished by a low total TPC, weak antioxidant activity, and weak antibacterial activity against S. enteritidis (ATCC 13076); lovage EO by low TPC, weak antioxidant activity, but moderate antibacterial activity; and basil EO by low TPC, moderate antioxidant activity, and weak antibacterial activity against L. monocytogenes (ATCC 19114).

RESEARCHES CONCERNING CONTAMINATION WITH STAPHYLOCOCCI DURING RAW MILK PROCESSING

Food toxi-infection are defined like acute diseases which appear sporadic or epidemic after consumption of food contaminated with different types of bacteria and their toxins, characterized through gastroenteritis symptomatic. Staphylococci are pathogen bacteria and conditioned pathogen bacteria with a pronounced tropism for cutaneous tissue causing therefore infections at this level. Also they can invade other tissues and organs and can provoke septicaemias and food toxi-infections. Staphylococci food toxi-infection that refers this paper was track down during an epidemiologic investigation accomplished by Sălaj Sanitary-Veterinary and Food Safety Department (DSVSA) to a milk processing centre. Epidemiologic investigation carried out by DSVSA inspectors together with samples analyses made into microbiology laboratory by the same institution brought out that an employee was responsible of staphylococci infection. This person transmitted the staphylococci through palm teguments. Also the responsibility belongs to the supervisor that had not verified periodical medical analyses and had not observed the lack of theme. Identification methods of staphylococci involved in this food toxi-infection were those standardised. Conform to SR ISO 6888/1/2/2002 AC/2005 were used enrichment, isolation and confirmation mediums. This case of food poisoning demonstrates one more time that irresponsibility and lack of a rigorously control of staff involved in production can leads to mass illness. We can conclude that in the chain of food processing the responsibility of producer is to follow all the steps so that the final product to be safety for the consumers.

RESEARCHES CONCERNING THE PROTEOLITICAL MODIFICATIONS DURING THE FERMENTATION AND THE STORAGE OF DAIRY PRODUCT-SANA

In this study were followed biochemical modifications of dairy product-sana, during processing. The researches were focused on two main working directions: n- appreciation of raw milk quality; n- dairy product-sana amino–acids determination by gas chromatography method.