There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

http://www.brasnutri.org.br/arquivos/estudos_tecnicos/Bioactive_peptides_Production_and_functionality.pdf

Bioactive peptides: Production and functionality

Phenolics in cereals, fruits and vegetables: Occurrence, extraction and analysis

Rennet-coagulated cheeses are ripened for periods ranging from about two weeks to two or more years depending on variety. During ripening, microbiological and biochemical changes occur that result in the development of the flavour and texture characteristic of the variety. Biochemical changes in cheese during ripening may be grouped into primary (lipolysis, proteolysis and metabolism of residual lactose and of lactate and citrate) or secondary (metabolism of fatty acids and of amino acids) events. Residual lactose is metabolized rapidly to lactate during the early stages of ripening. Lactate is an important precursor for a series of reactions including racemization, oxidation or microbial metabolism. Citrate metabolism is of great importance in certain varieties. Lipolysis in cheese is catalysed by lipases from various source, particularly the milk and cheese microflora, and, in varieties where this coagulant is used, by enzymes from rennet paste. Proteolysis is the most complex biochemical event that occurs during ripening and is catalysed by enzymes from residual coagulant, the milk (particularly plasmin) and proteinases and peptidases from lactic acid bacteria and, in certain varieties, other microorganisms that are encouraged to grow in or on the cheese. Secondary reactions lead to the production of volatile flavour compounds and pathways for the production of flavour compounds from fatty acids and amino acids are also reviewed.

/pdf/biochemistry-of-cheese-ripening-ukq5dvnz64.pdf

Biochemistry of Cheese Ripening

Coronary heart disease

Characterization and fractionation of phenolic compounds extracted from olive oil mill wastewaters

The authentication and quality assessment of virgin olive oil were performed using high-resolution 1H and 13C NMR spectroscopy. An overview of the various determinations currently assessed is presented with emphasis on the detection of adulteration with foreign (seed) oils and esterified or refined olive and olive-pomace oils. Recent results on the NMR analysis of natural compounds (diacylglycerols, free fatty acids, aldehydes, polyphenols, etc.) related to the quality-freshness of virgin olive oil are also reported. The possible contribution of high-resolution NMR to the authentication of geographical origin of virgin olive oil is discussed. © 1997 John Wiley & Sons, Ltd.

1H and 13C NMR of virgin olive oil. An overview

The isolation and identification of low molecular mass peptides formed during the ripening of Parmigiano-Reggiano cheese is described. A strategy was used based on the fractionation of nitrogenous material using chemical methods followed by HPLC to isolate peptides and fast atom bombardment-mass spectrometry to identify them. It was found that the majority of cheese oligopeptides arose from the proteolysis of β-casein. Several phosphopeptides and oligopeptides known in vivo to be biologically active have also been identified during the ripening of cheese.

Characterization of the 12% trichloroacetic acid-insoluble oligopeptides of Parmigiano-Reggiano cheese

High-field (600 MHz) nuclear magnetic resonance (NMR) spectroscopy was applied to the direct analysis of virgin olive oil. Minor components were studied to assess oil quality and genuineness. Unsaturated and saturated aldehyde resonances, as well as those related to other volatile compounds, were identified in the low-field region of the spectrum by two-dimensional techniques. Unsaturated aldehydes can be related to the sensory quality of oils. Other unidentified peaks are due to volatile components, because they disappear after nitrogen fluxing. The statistical analysis performed on the intensity of these peaks in several oil samples, obtained from different olive varieties, allows clustering and identification of oils arising from the same olive variety. Diacylglycerols, linolenic acid, other volatile components, water, acetic acid, phenols, and sterols can be detected simulteneously, suggesting a useful application of high-field NMR in the authentication and quality assessment of virgin olive oil.

Raffaele Sacchi

Papers

Characterization and fractionation of phenolic compounds extracted from olive oil mill wastewaters

1H and 13C NMR of virgin olive oil. An overview

Characterization of the 12% trichloroacetic acid-insoluble oligopeptides of Parmigiano-Reggiano cheese

A high-field1H nuclear magnetic resonance study of the minor components in virgin olive oils

Characterization of phenolic extracts from olives (Olea europaea cv. Pisciottana) by electrospray ionization mass spectrometry