Impact of adding prebiotics and probiotics on the characteristics of edible films and coatings- a review.

Nowadays, conventional packaging materials made using non-renewable sources are being replaced by more sustainable alternatives such as natural biopolymers (proteins, polysaccharides, and lipids). Within edible packaging, one can differentiate between edible films or coatings. This packaging can be additivated with bioactive compounds to develop functional food packaging, capable of improving the consumer's state of health. Among the bioactive compounds that can be added are probiotics and prebiotics. This review novelty highlighted recent research on edible films and coatings additivated with probiotics and prebiotics, the interactions between them and the matrix and the changes in their physic, chemical and mechanical properties. When bioactive compounds are added, critical factors must be considered when selecting the most suitable production processes. Particularly, as probiotics are living microorganisms, they are more sensitive to certain factors, such as pH or temperature, while prebiotic compounds are less problematic. The interactions that occur inside the matrix can be divided into two main groups: covalent bonding (-NH2, -NHR, -OH, -CO2H, etc) and non-covalent interactions (van der Waals forces, hydrogen bonding, hydrophobic and electrostatic interactions). When probiotics and prebiotics are added, covalent and non-covalent interactions are modified. The physical and mechanical properties of films and coatings depend directly on the interactions that take place between the biopolymers that form their matrix. Greater knowledge about the influence of these compounds on the interactions that occur inside the matrix will allow better control of these properties and better understanding of the behaviour of edible packaging additivated with probiotics and prebiotics.

Rewiring of the apoptotic TGF-ß-SMAD/NFκB pathway through an oncogenic function of p27 in human papillary thyroid cancer.

Papillary thyroid carcinoma (PTC), the most frequent thyroid cancer, is characterized by low proliferation but no apoptosis, presenting frequent lymph-node metastasis. Papillary thyroid carcinoma overexpress transforming growth factor-beta (TGF-ß). In human cells, TGF-ß has two opposing actions: antitumoral through pro-apoptotic and cytostatic activities, and pro-tumoral promoting growth and metastasis. The switch converting TGF-ß from a tumor-suppressor to tumor-promoter has not been identified. In the current study, we have quantified a parallel upregulation of TGF-ß and nuclear p27, a CDK2 inhibitor, in samples from PTC. We established primary cultures from follicular epithelium in human homeostatic conditions (h7H medium). TGF-ß-dependent cytostasis occurred in normal and cancer cells through p15/CDKN2B induction. However, TGF-ß induced apoptosis in normal and benign but not in carcinoma cultures. In normal thyroid cells, TGF-ß/SMAD repressed the p27/CDKN1B gene, activating CDK2-dependent SMAD3 phosphorylation to induce p50 NFκB-dependent BAX upregulation and apoptosis. In thyroid cancer cells, oncogene activation prevented TGF-ß/SMAD-dependent p27 repression, and CDK2/SMAD3 phosphorylation, leading to p65 NFκB upregulation which repressed BAX, induced cyclin D1 and promoted TGF-ß-dependent growth. In PTC samples from patients, upregulation of TGF-ß, p27, p65 and cyclin D1 mRNA were significantly correlated, while the expression of the isoform BAX-ß, exclusively transcribed in apoptotic cells, was negatively correlated. Additionally, combined ERK and p65 NFκB inhibitors reduced p27 expression and potentiated apoptosis in thyroid cancer cells while not affecting survival in normal thyroid cells. Our results therefore suggest that the oncoprotein p27 reorganizes the effects of TGF-ß in thyroid cancer, explaining the slow proliferation but lack of apoptosis and metastatic behavior of PTC.

Benzo(a)pyrene penetration on a smoked meat product during smoking time.

The Codex Alimentarius gives recommendations to prevent carcinogenic polycyclic aromatic hydrocarbons (PAH) (represented by benzo(a)pyrene (BaP)) contamination during processing of meat products, including the control of smoking time. The influence of direct smoking time (0, 1, 3, 5 and 7 days) on the relationship between the BaP and moisture content of a typical Spanish smoked meat product called chorizo and the mechanism of BaP penetration and water release from four different depths in the product was studied. Chorizo was studied from the Principality of Asturias, a location never before tested. An analytical method was developed for this purpose consisting of PAH extraction assisted by sonication followed by solid-phase extraction (SPE) sample clean-up and analytical determination using GC-MS. Results show that an increase in smoking time produced contradictory and independent effects on the moisture and BaP content (µg kg⁻¹) of chorizos. The moisture content decreased from 49.9% to 31.3%. On the other hand, the BaP content increased from less than 0.24 µg kg⁻¹ to 0.75 µg kg⁻¹, finally stabilising after 5 days of smoking. After this time, the natural pores of the casing could be blocked by the large size tar particles from smoke, preventing the continued penetration of PAHs. The BaP content decreased and the moisture content increased progressively from the casing to the centre of the meat product. BaP mainly accumulated in the smoked casing, being four times in excess of the legal limit. This paper analyses the mechanism for preventing PAHs contamination during the process of smoking meat products.

Identification of a paired box gene 8-peroxisome proliferator-activated receptor gamma (PAX8-PPARgamma) rearrangement mosaicism in a patient with an autonomous functioning follicular thyroid carcinoma bearing an activating mutation in the TSH receptor.

Our main objective was to search for mutations in candidate genes and for paired box gene 8-peroxisome proliferator-activated receptor gamma (PAX8-PPARgamma) rearrangement in a well-differentiated angioinvasive follicular thyroid carcinoma (FTC) causing hyperthyroidism. DNA and RNA were extracted from the patient's thyroid tumor, as well as 'normal' thyroid tissue, and from peripheral blood lymphocytes (PBLs) of the patient, her daughter, and two siblings. Nuclear isolation was extracted from the patient's tumor, 'normal' thyroid tissue, PBLs, and uterine leiomyoma tissue. TSH receptor (TSHR), RAS, and BRAF genes were sequenced. We searched for PAX8-PPARgamma in thyroid, PBL, and uterine leiomyoma samples from the patient and family members. Proliferative effects of detected mutants on non-transformed human thyrocytes cultures. An activating TSHR mutation, M453T, was detected in the tumor. PAX8 (exons 1-8+10)-PPARgamma was found in all tested patient's tissues. A second rearrangement, PAX8 (exons 1-8)-PPARgamma, was detected in the patient's normal thyroid tissue. Under deprived medium condition, co-transfection of PAX8-PPARgamma and TSHR-M453T dramatically increased the number of thyrocytes, an effect that it was not observed with TSHR wild-type (WT); under complete medium conditions, co-transfection of PAX8-PPARgamma with either TSHR-M453T or TSHR-WT inhibited cell proliferation. We report a patient with hyperthyroidism due to a FTC bearing an activating TSHR mutation and PAX8-PPARgamma rearrangements. PAX8-PPARgamma was present as a mosaicism affecting tissues from endodermal and mesodermal origin. PAX8-PPARgamma and TSHR-M453T inhibited or promoted thyrocyte proliferation depending on medium conditions. The activating TSHR mutation could promote in vivo FTC development in PAX8-PPARgamma-positive thyrocytes under poor blood supply with deprivation of growth factors but restraint the tumor growth when growth factors are supplied.

Regulation of visceral adipose tissue-derived serine protease inhibitor by nutritional status, metformin, gender and pituitary factors in rat white adipose tissue.

Visceral adipose tissue-derived serine protease inhibitor (vaspin) is a recently discovered adipocytokine mainly secreted from visceral adipose tissue, which plays a main role in insulin sensitivity. In this study, we have investigated the regulation of vaspin gene expression in rat white adipose tissue (WAT) in different physiological (nutritional status, pregnancy, age and gender) and pathophysiological (gonadectomy, thyroid status and growth hormone deficiency) settings known to be associated with energy homeostasis and alterations in insulin sensitivity. We have determined vaspin gene expression by real-time PCR. Vaspin was decreased after fasting and its levels were partially recovered after leptin treatment. Chronic treatment with metformin increased vaspin gene expression. Vaspin mRNA expression reached the highest peak at 45 days in both sexes after birth and its expression was higher in females than males, but its levels did not change throughout pregnancy. Finally, decreased levels of growth hormone and thyroid hormones suppressed vaspin expression. These findings suggest that WAT vaspin mRNA expression is regulated by nutritional status, and leptin seems to be the nutrient signal responsible for those changes. Vaspin is influenced by age and gender, and its expression is increased after treatment with insulin sensitizers. Finally, alterations in pituitary functions modify vaspin levels. Understanding the molecular mechanisms regulating vaspin will provide new insights into the pathogenesis of the metabolic syndrome.

Effect of processing on functional properties of animal blood plasma.

A number of functional and physical properties such as solubility, foam capacity, emulsifying stability and interfacial tension were compared for standard plasma, plasma decationed by ion exchange and plasma deionized by ultrafiltration (UF). The changes in functional properties can determine the use of a protein as an additive to a food product or invalidate its use. All samples had good functional properties and hence could be used in the formulation of food products. Results showed that ion exchange and UF improved emulsifying capacity while having little effect on the other functional properties.

Demineralization of animal blood plasma by ion exchange and ultrafiltration.

The blood waste from slaughterhouses is strictly controlled due to its high pollutant load, the treatment for its purification being of great economic interest. The separation of proteins, the most valuable components of blood, in a chromatographic column requires the use of well treated plasma, in particular the removal of inorganic salts. Accordingly, a demineralization process is usually required. In this paper, ion exchange and ultrafiltration demineralization techniques were tested and the results compared. In the ion exchange experiments, the blood plasma was treated with cationic and anionic resins in packed columns, studying the removal of the major cations and anions, protein loss and pH evolution in both the loading and elution steps. In the demineralization process by means of membranes, a 10KDa ultrafiltration membrane was used, the blood plasma being filtered to concentrate all the proteins in the retentate while removing the inorganic ions and other compounds in the permeate. The evolution of the major anions and cations in the plasma and the protein loss were studied at different volumetric concentration factors. The results obtained enable us to draw conclusions as regards the advantages and disadvantages of each technique at a laboratory scale and to offer some considerations regarding the operation at an industrial scale.

Rheological behavior and organoleptic effects of ovalbumin addition in yogurt mousse production.

Yogurt mousse is a novel, high added-value dairy product that has been well received by the market. This paper presents a study of the effect of the addition of ovalbumin to the product on its rheological and organoleptic qualities. The ovalbumin was previously separated from egg white with a high grade of purity using an ion exchange resin synthesized by the authors. Diverse rheological tests at different temperatures and corresponding sensorial assessments were conducted to compare samples without and with added ovalbumin. The obtained results confirm that the product is viscoelastic and combines the properties of foams and emulsions; the elastic component is greater than the viscous component. Moreover, at temperatures ranging from 5 to 15 degrees C, a usual interval of consumption, the product behaves rheologically in a similar way. Conversely, the addition of ovalbumin under the assayed conditions also makes the elastic character of the product increase at a given temperature. Finally, the sensorial assessment tests and determinations of stability and volume yield enabled us to verify that the addition of ovalbumin at an amount of 1.3% hardly alters the stability, resistance to shear stress, or the texture and improves the degree of foaming. Therefore, the product with additive is of good commercial quality.

Egg-white protein fractionation using new weak anion-exchange resins based on poly(glycidyl methacrylate-co-ethylendimethacrylate). Preparation and characterization.

A new formulation for a poly(glycidyl methacrylate-co-ethylendimethacrylate)-based resin with a 11:9 proportion of monomer to crosslinker is developed and amino-functionalized in order to obtain new particulate materials suitable for egg-white protein fractionation. Functionalization is carried out using three different chemical reagents: diethylamine (DEA), DEA-tetrahydrofuran (THF) (1:1), and concentrated ammonia. The ammonia- and DEA-THF-treated polymers are used to fractionate egg-white proteins, in particular lysozyme and ovalbumin, by anion-exchange chromatography in packed column experiments, the latter resin showing better performances. Finally, both supports, working at semipreparative scale and step-gradient elution, separate pure ovalbumin with a yield of 83%.

Bovine plasma protein fractionation by ion exchange chromatography.

An ion exchange chromatography process was developed to separate the main protein fractions of bovine blood plasma using a composite material, Q-HyperD resin, and a gel material, DEAE-Sepharose. The experiments were carried out at semipreparative scale. It was necessary to establish analytical methods of electrophoresis and HPLC to identify the fractionated proteins. Results show that these materials are able to adequately fractionate different protein groups from the raw blood plasma. This method may be used to avoid chemical fractionation using agents such as ethanol or PEG and, thus, decrease protein denaturation of the different fractions to be used for research or pharmaceutical purposes. The Q-HyperD resin presents a better retention capacity for plasma protein than DEAE-Sepharose under the experimental conditions employed.

Coupling process for plasma protein fractionation using ethanol precipitation and ion exchange chromatography.

Blood is one of the most polluting by-products of the meat industries. Technologies have been developed to recover the proteins contained in blood, and in this study, a process coupling chemical precipitation with ion exchange chromatography was developed to separate and purify the main protein fractions of blood plasma. Ethanol was used as the agent for precipitation and Q-HyperD was used to purify the proteins by chromatography. To monitor all the steps and operations, analytical methods of electrophoresis and HPLC were stablished to identify the fractionated proteins. The results show that this process can recover the main plasma proteins with a high degree of purity for use in the pharmaceutical and food industries.

Localization of the thermosensitive X-prolyl dipeptidyl aminopeptidase in the vacuolar membrane of Saccharomyces cerevisiae.

Most of the X-prolyl dipeptidyl aminopeptidase activity of Saccharomyces cerevisiae was found to be associated with purified vacuolar membranes (specific activity approx. 75-times higher than in the protoplast lysate). The tonoplast-bound enzyme is thermosensitive. Another heat-resistant enzyme was found in the protoplast lysate. The tonoplast-bound thermosensitive enzyme shows an apparent Km of 0.06 mM against L-alanyl-L-prolyl-p-nitroanilide while the heat-resistant enzyme shows an apparent Km of 0.4 mM against the same substrate.

Studies on the regulation of X-prolyl dipeptidyl aminopeptidase activity.

The specific activity of X-prolyl-dipeptidyl aminopeptidase in Saccharomyces cerevisiae grown on glucose-containing medium remains constant during exponential growth and increases less than twofold when cells reach the stationary phase. In cells harvested from exponential growth on glucose-containing medium the specific activity of the enzyme is found to be 20-30% lower than the specific activity observed in media without glucose, containing acetate or ethanol as the carbon source. X-Prolyl-dipeptidyl aminopeptidase is not inactivated after the addition of glucose to stationary phase cells. Growth of the yeast on poor nitrogen sources or under nitrogen-starvation results in a three- to fourfold increase in the level of the enzyme.