ANALYSIS OF NATURALLY OCCURRING PHENOLIC COMPOUNDS IN AROMATIC PLANTS BY RP-HPLC AND GC-MS AFTER SILYLATION

Aromatic plants of Greek origin, Origanum dictamnus (dictamus), Eucalyptus globulus (eucalyptus), Origanum vulgare L. (oregano), Mellisa officinalis L. (balm mint) and Sideritis cretica (mountain tea) were examined for the content of phenolic substances. Reversed phase high performance liquid chromatography was used for the analysis of the plant extracts. Gas chromatography–mass spectrometry method was also used for identification of phenolic compounds after silylation. The most abundant phenolic acids were gallic acid (1.5–2.6 mg 100 g ^{− 1} dry sample), ferulic acid (0.34–6.9 mg 100 g ^{− 1} dry sample) and caffeic acid (1.0–13.8 mg 100 g ^{− 1} dry sample). ( + )-Catechin and ( − )-epicatechin were the main flavonoids identified in oregano and mountain tea. Quercetin was detected only in eucalyptus and mountain tea.

PRACTICAL APPLICATIONS

Plant-derived polyphenols receive considerable interest because of their potential antioxidant and antimicrobial properties. Undoubtedly, it is very important not only to determine those properties but also to determine each and every phenol in aromatic plants both qualitatively and quantitatively. A number of analytical methods have been proposed for the separation and determination of these compounds. Most of these protocols are based on a high performance liquid chromatography technique with ultraviolet spectrophotometry. Gas chromatography–mass spectrometry after silylation of the phenolic compounds is used in this research together with the aforementioned technique as an alternative and more sensitive method to detect and understand the compositional profile of the extracts as well as the structure and functional relationship of the components in the extracts, based on MS spectra.     

Laboratory and Pilot Scale Recovery of Protein from Mechanically Separated Chicken Residue

Bone residue resulting from mechanical deboning of chicken backs and necks was subjected to alkali extraction followed by acid precipstation to recover food grade protein. A laboratory study of effects of varying die size in the grinding of the starting material, of extraction temperature, and of g-force during centrifugation on composition of process fractions was conducted. Grinding increased ash content, higher temperature reduced fat content, and increasing centrifugal force decreased ash content, of the final products. Effects of grinding, extraction temperature, and centrifugal type were also studied on a pilot scale. Final protein product yield was higher at a 22°C than at a 3–7°C extraction temperature, and less fat was incorporated using a basket centrifuge than with a horizontal decanter centrifuge.     

GROWTH OF EUROTIUM CHEVALIERI IN MILK JAM: INFLUENCE OF PH, POTASSIUM SORBATE AND WATER ACTIVITY

Milk jam (dulce de leche) is a typical Argentine sweet spread prepared by milk evaporation to about 70% w/w total solids at atmospheric pressure with added sucrose, glucose and vanillin. Growth of xerophilic molds represents a severe problem in this type of intermediate moisture product. This study evaluated the growth response of Eurotium chevalieri in milk jam with different potassium sorbate (KS) concentrations (0, 500, 1,000, 1,500 and 2,000 ppm) at selected water activity (a_w) values (?0.80 and 0.85) and two pH levels (?5.5 and 6.0) stored at room temperature (25C) for 90 days. Growth curves were characterized by the modified Gompertz model, and the effect of the independent variables on the estimated parameters (maximum specific growth rate, v_m, and lag time, λ) was analyzed through polynomial equations. Growth of E. chevalieri was prevented for at least 90 days when the addition of 1,000 ppm KS was combined with a decrease in a_w to 0.80 and ph 5.5. The boundary between growth and nongrowth of E. chevalieri as a function of a_w, pH, KS and storage time was also predicted by means of the probabilistic model using logistic regression, which provided a wide range of formulation possibilities depending on the targeted shelf life.     

Interactions Among Calcium, Zinc and Phytate with Three Protein Sources

Various combinations of calcium (4.94 mmol), zinc (0.0071 mmol) and phytate (0.284 mmol) were added either to soy concentrate, casein or torula yeast to determine effects of their interaction on in vitro solubility of protein, calcium, zinc, and phytate (PA). Two Ca sources, calcium carbonate (CaCO₃) and calcium-citrate-malate complex (CCM) were used. Two pH levels, 2.0 and 5.5, were used to simulate gastrointestinal pH conditions. An increase in pH significantly reduced (P<0.01) Zn solubility in all treatments with all protein sources. The solubility of Ca and PA were significantly decreased (P< 0.01) when both components were present probably due to formation of insoluble Ca-PA complexes. At pH 5.5, with casein and yeast proteins, Zn was significantly more (P< 0.01) soluble in samples with CCM, in the absence of PA, than in those with CaCO₃.     

The London Conceptualists

This article examines the formation, activities, and significance of a group dubbed the "London Conceptualists" by Peter Cook that were students of Bernard Tschumi at the Architectural Association School of Architecture during the mid-1970s. Through RoseLee Goldberg, director of the Royal College of Art, the students were introduced to theories of performance along with radical experiments in performance art. Goldberg's conception of space as an arena for the realization of theory goaded the London Conceptualists away from writing and drawing toward installations and performance in disused buildings. This article situates their activities in London in the late 1970s and analyzes their relationship to other performance art practices and to conceptual architecture.     

Heterogeneity of shale documented by micro‐FTIR and image analysis

In this study, four New Albany Shale Devonian and Mississippian samples, with vitrinite reflectance [R_o] values ranging from 0.55% to 1.41%, were analyzed by micro‐FTIR mapping of chemical and mineralogical properties. One additional postmature shale sample from the Haynesville Shale (Kimmeridgian, R_o = 3.0%) was included to test the limitation of the method for more mature substrates. Relative abundances of organic matter and mineral groups (carbonates, quartz and clays) were mapped across selected microscale regions based on characteristic infrared peaks and demonstrated to be consistent with corresponding bulk compositional percentages. Mapped distributions of organic matter provide information on the organic matter abundance and the connectivity of organic matter within the overall shale matrix. The pervasive distribution of organic matter mapped in the New Albany Shale sample MM4 is in agreement with this shale's high total organic carbon abundance relative to other samples. Mapped interconnectivity of organic matter domains in New Albany Shale samples is excellent in two early mature shale samples having R_o values from 0.55% to 0.65%, then dramatically decreases in a late mature sample having an intermediate R_o of 1.15% and finally increases again in the postmature sample, which has a R_o of 1.41%. Swanson permeabilities, derived from independent mercury intrusion capillary pressure porosimetry measurements, follow the same trend among the four New Albany Shale samples, suggesting that micro‐FTIR, in combination with complementary porosimetric techniques, strengthens our understanding of porosity networks. In addition, image processing and analysis software (e.g. ImageJ) have the capability to quantify organic matter and total organic carbon – valuable parameters for highly mature rocks, because they cannot be analyzed by micro‐FTIR owing to the weakness of the aliphatic carbon–hydrogen signal.     

Consumer acceptability and purchase intent of probiotic yoghurt with added glucose oxidase using sensometrics,artificial neural networks and logistic regression

This research aimed to identify the drivers of acceptance and purchase intent of a probiotic (Bifidobacterium longum BL05) nonflavoured yoghurt supplemented with glucose oxidase, and to model the consumers’ acceptability using sensometrics and artificial neural networks (ANN). Consumers (n = 100) evaluated the degree of liking of yoghurt assays in respect of appearance, aroma, taste, texture and overall linking. Sensometric techniques – multiple linear regression (MLR), partial least squares regression (PLS), principal component regression (PCR) – and ANN were used to model the overall liking. Sensory drivers of global acceptance and purchase intent were also determined using logistic regression (LR). Hierarchical cluster analysis (HCA) identified three consumer segments that presented differences in all sensory attributes evaluated (P < 0.05). The ANN model showed the best performance to predict overall liking, followed by the MLR, PLS and PCR, indicating that taste and texture were the most significant attributes impacting the yoghurts overall liking. In accordance with the logistic models, overall acceptance and purchase intent could be predicted with 81.94 and 85.49% accuracy, respectively. The logistic regression indicated that taste was the attribute that contributed significantly (P < 0.0001) to higher scores for purchase intent and was considered the driver of acceptance.     

Microbial diversity and dynamics of Pecorino di Filiano PDO,a traditional cheese of Basilicata region (Southern Italy)

The evolution of microbial populations of ‘Pecorino di Filiano’ (PF) cheese was investigated during ripening in natural cave and storeroom. 62.5% of isolates grow at 45 and 15 °C and 77.7% showed high salt concentrations tolerance. Brevibacterium linens was dominant in surface samples. Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus paracasei subsp. paracasei were more frequently isolated both surface and core samples, while Leuconostoc lactis and Leuconostoc mesenteroides subsp. mesenteroides prevailed among Leuconostoc isolates. Our results suggest the importance of the ripening environment of cheeses and how a biological ecosystem affects and produces the typical features of artisanal products.