STORAGE STABILITY OF DRIED ONION

The effect of predrying treatment and conditions of storage on color stability of dried onion was investigated. The variety of onion had little effect on color stability, but storage time prior to drying affected the color of the dried onion. Steeping of sliced onion in water or dipping in starch solution lessened browning and allowed for longer storage. Ascorbic acid in the steeping solution yielded dried onion with a pink unacceptable color. Osmotic dewatering imparted a yellow color to the onion, but improved the color stability of the dried product. Light was an important variable in the storage stability of dried onion.     

CORRELATION AMONG METALLIC IONS,PHENOLIC COMPOUNDS AND ANTIMICROBIAL ACTION IN MEDICINAL PLANTS EXTRACTS

ABSTRACT

The extracts of three different medicinal plants –Calendula officinalis L., Maytenus ilicifolia Martius ex Reissek and Cymbopogon citratus (DC) Stapf – obtained with 70% and 95% v/v ethanol had their antimicrobial activity tested against five pathogenic microorganisms. A quantitative analysis of total phenols, flavonoids and mineral species was performed on the extracts using UV‐vis spectroscopy and atomic absorption spectroscopy. Klebsiella pneumoniae showed the greatest sensibility to the extracts tested. The mineral content of the medicinal herbs varied according to the type of plant (Cu = not detected to 10.90; Zn = 0.85 to 10.04; Na = 24.94 to 153.62; Al = 90.04 to 420.39; Mg = 9.62 to 1,129.15; Ca = 7.15 to 167.27 and K = 913.85 to 9,578.94 µg/g); however, the concentration of heavy elements (Pb, Cd and Cr) was null in the extracts. The concentrations of flavonoids ranged from 13.55 to 41.54 mg/g and 92.35 to 518.28 mg/g for phenolic acids.

PRACTICAL APPLICATIONS

The use of plants with pharmacological activities has increased significantly because of their functional properties in the diet for the promotion of human health and antimicrobial effects. Moreover, medicinal herbs play an important role in public health, especially in developing countries. In Brazil, the use of plant extracts in the treatment of certain diseases is very common. This habit can be explained, at least in part, by the belief that herbs with therapeutic effects do not have toxic effects on the organism. In this paper, ethanolic extracts of three medicinal plants, widely cultivated and used by the population of Brazil and worldwide, had their levels of metals ions and total phenolic compounds determined. Antimicrobial activity of the extracts was evaluated against foodborne pathogens or food spoilage organisms or clinically isolates microorganisms.

     

INFLUENCE OF NICOTINE AND DIPHENYLAMINE ON THE CAROTENOID COMPOSITION OF RHODOTORULA STRAINS

In order to obtain commercially interesting carotenoid profiles, the effect of supplementation with diphenylamine (DPA) and nicotine in the culture media of Rhodotorula rubra and Rhodotorula glutinis was studied. Fermentation experiments were carried out in flasks. The carotenoids were extracted with ethyl acetate by physical disruption, and analyzed by high‐performance liquid chromatography using a reversed‐phase column. At subinhibitory levels, both the inhibitors showed no effect on yeast growth for the two strains. Only R. rubra produced more carotenoids when 5 μmol of DPA was added to the broth, 155.8 μg/g of dry weight. For both strains, supplementation with 5 μmol DPA caused a significant reduction in the torularhodin/torulene ratio, from 1.5 to 0.5 for R. rubra, and from 0.8 to 0.5 for R. glutinis. With 10 μmol of this inhibitor, an accumulation of β‐carotene occurred from 13 to 47% in R. rubra, and from 36 to 43% in R. glutinis. Supplementation with nicotine resulted in the selective biosynthesis of lycopene (up to 93.8 μg/g) and the formation of a minor carotenoid, tentatively identified as 3,4‐didehydrolycopene, not previously related to Rhodotorula spp.     

Incidence of autochthonous Argentinean mixed starter cultures in ripening of slurry cheese models

The effect of three mixed autochthonous starter cultures in ripening profiles of experimental semihard goat cheeses was evaluated under controlled microbiological conditions. Enterococcus faecium ETC3 and ETC6, Lactobacillus plantarum ETC17 and L. rhamnosus ETC14 were used. Combination of all strains showed the highest level of water soluble nitrogen fraction and total free amino acids (TFAA) at ripening day 1, the lowest level of phosphotungstic acid nitrogen soluble fraction and TFAA at ripening day 64 and the highest global impression. Principal component analyses were performed to establish amino acid profiles relations in the samples.     

Particulate Lead in Water Supplies

This paper describes research in areas where the occasional failure to meet the EC standard for lead in drinking water is due to the presence of particulate lead. A method is described to disinguish between soluble, particulate and colloidal lead in tap water, and characteristics are given of water sources which are most likely to suffer from this form of lead problem. At least two types of particulate (insoluble) lead in tap water have been identified, and some factors are discussed which cause the occurrence of both types. Interim results of trials are presented, with remedial actions.     

Mesenchymal stem cell secretome and nanotechnology: Combining therapeutic strategies

Mesenchymal stem cells (MSC) have pushed the field of stem cell-based therapies by inducing tissue regeneration, immunosuppression, and angiogenesis mainly through vesicles and soluble factors release (paracrine signaling). MSC-extracellular vesicles (MSC-EV) adaptable secretome and homing to injured sites allowed researchers to unlock a new era of cell-free based therapy. In parallel, nanoparticles (NP) have been explored in contributing to transport and drug delivery systems, giving drugs desired physical-chemical properties to exploit cell behavior. However, NPs can be quickly recognized by immune cells and cleared from circulation. In this viewpoint, we explore how combining both therapeutic strategies can improve efficacy and circumvent limitations of both therapies. MSCEV benefit from the potent MSC membrane composition, guiding chemotaxis to tumor sites, a very restricted microenvironment. MSC-EV has low immunogenicity, high stability, long half-life and can explore tissue targeting ligands as a precise drug carry, even across biological barriers. Those properties promote enhanced targeted drug delivery that can be combined with NP, exploring biological membrane production through: 1. direct cell therapy with NP-infused MSC; 2. NP-containing MSC-EV generated by NP-infused MSC; 3. by coating NP in MSC membrane (“MSC NanoGhosts”), allowing precise cargo definition without losing targeting. Therefore, nanotechnology combined with cell-based therapeutic resources can greatly improve targeted drug delivery, improving efficacy and opening a new venue of therapeutic possibilities.     

Effect of probiotic lactobacilli on faecal enzyme and genotoxic activity in human faecal water in the presence of the carcinogen PhIP in vitro

The average β‐glucuronidase activity for children was 0.48 ± 0.04 U/mg, for adults 0.75 ± 0.27 U/mg and for elderly 1.55 ± 0.06 U/mg. For β‐glucosidase, it was 0.19 ± 0.02 U/mg for children, 0.77 ± 0.26 U/mg for adults and 1.18 ± 0.27 U/mg for elderly. In the presence of probiotics, the highest decrease in genotoxicity was observed for Lactobacillus casei 0908 (to 7.99 ± 1.32) and Lactobacillus paracasei 0919 (to 6.19 ± 1.44) for all children. In adults, lower mean genotoxicity was regarded after incubation of PhIP with L. casei 0908 (it was 5.27 ± 1.13) and L. paracasei 0919 (it was o 6.01 ± 1.00). For elderly, statistically significant decrease was maintained after incubation of PhIP with L. casei 0900 (to 6.72 ± 2.67).     

TRAINING A TEXTURE PROFILE PANEL AND CONSTRUCTING STANDARD RATING SCALES IN ARGENTINA

A method is described for constructing reference scales for the sensory texture profile method in countries outside the U. S., such as Argentina. A complete set of 13 reference scales were constructed for Argentine foods: hardness, adhesiveness to palate, fracturability, cohesiveness, denseness, wetness, adhesiveness to lips, roughness, selfadhesiveness, springiness, cohesiveness of mass, moisture absorption and adhesiveness to teeth. Scores given by the panel trained using these scales were compared to those given by a panel trained using the US scales and found to be similar, in direction and magnitude, among the tested food samples.     

INFLUENCE OF ENZYMES ON THE TEXTURE OF BROWN PAN BREAD

Enzymes are commonly used to improve the textural quality of bread and to extend its shelf life. To study the effect of enzymes on the texture of brown pan bread, four types of bread were industrially manufactured using amylase, xylanase, a mixture of amylase : xylanase (1:1) and control (no enzyme). After baking, the bread samples were stored for 1, 4, 7, 10, 13, 15 and 17 days. At each storage time, bread texture was evaluated by sensory and instrumental methods, and the overall acceptability was determined. Instrumental and sensory texture data showed that the addition of amylase or amylase : xylanase decreased the staling rate of breads. Furthermore, the use of a mixture of amylase and xylanase provided better results than the addition of amylase alone. Therefore, the results suggest that the addition of a mixture of amylase and xylanase is recommended to extend the shelf life of brown pan bread. On the other hand, the addition of xylanase resulted in an increase of the staling rate. The results suggest that when xylanase is used to improve dough machinability, the addition of amylase along with it should be considered in order to prevent an increase of staling rate.