The Clarifying Reagent, or how to make the analysis of milk and dairy products easier
Difficulties with the analysis of opaque milk and dairy products can be resolved by rendering the sample transparent. This allows direct photometric measurements of the reaction mixtures, and all sample pre-treatment steps become unnecessary. For this, several reagents have been reported in literature. Among them, the ‘Clarifying Reagent’ is mainly described here: its composition is given because it is now released from patenting restrictions. Its main property is a low absorbance between 340 and 800 nm. So it can be used in many chemical and enzymatic colorimetric measurements for estimating the quality of milk and dairy products.
Assessment and validation of methods for the determination of γ-glutamyltransferase activity in sheep milk
Abstract The determination of enzymatic activity in sheep milk is still today a practically unexplored field of research. This study proposes and fully validates two analytical procedures (i.e. by means of UV–vis spectrophotometry and RP-HPLC methods) for the determination of γ-glutamyltransferase activity in sheep milk. Both methods are characterised by low detection and quantification limits, excellent linearity over a wide enzymatic activity interval, very good repeatability and reproducibility, and are bias-free. The RP-HPLC method provides better sensitivity and automation capability levels than that of UV–vis, and its use is hence suggested for screening purposes. These methods have been preliminarily tested with a number of real samples of whole sheep milk, obtaining an average γ-glutamyltransferase activity value of 2.93 ± 0.50 U ml −1 and a range from 2.72 ± 0.10 U ml −1 to 3.46 ± 0.11 U ml −1 .
The status of FAO and codex alimentarius developments on vegetable proteins
The FAO is interested in increasing world protein supplies both by advising and assisting developing countries to increase their production of staple foods and by encouraging the development of technology to produce protein concentrates both from vegetable and animal sources to supplement diets which are low in protein content. Recent revisions of the amount of protein required in the diet in relation to total per capita energy requirements and the difficulties encountered in introducing novel foods into established dietary patterns has led FAO to concentrate on increased agricultural productions in developing countries as the primary means of combatting malnutrition. In the meantime, in North America and Europe, advances in the technology of processing vegetable proteins has given highly acceptable products simulating meats which are being used as meat extenders and meat analogues. The consequent increase in vegetable protein production has revealed a need for international, agreement on standardization, and it has been agreed that this will be undertaken by the Joint FAO/WHO Food Standards’ Programme. The program operates chiefly through the Codex Alimentarius, Commission, an international governmental body, the purpose of which is to protect consumers against health hazard in food and against fraud. The Commission, which has 116 member governments, controls an intensive program of work covering the composition, labeling, additives, contaminants, pesticide residues, hygiene, sampling and analysis aspects of foods and has established a procedure which allows member governments ample opportunity to reach agreement on food standards and to accept them for incorporation into national legislation. The Codex Commission, at its 12th session, decided to establish a Committee on Vegetable Proteins with the following terms of references: “to elaborate definitions and world-wide standards for vegetable protein products deriving from soybeams, cottonseed, groundnuts, cereals and from other vegetable sources as they come into use for human consumption, and to elaborate guidelines on utilization of such vegetable protein products in the food supply system, on nutritional requirements and safety on labeling and on other aspects as may seem appropriate.” The question of which country will host the Committee is still under discussion.