The Laemmegroup Laboratory of Moncalieri (Italy) has been active in the field of histology since 2009. For about two years, the Laboratory has been providing food histology services for the compositional quality assessment of meat-based products – for instance, the detection of any residues deriving from previous food processing steps.
In addition to this analytical service, the Laboratory has recently introduced a new method allowing to identify the presence of gelling agents, thickeners and stabilisers in meat-based products.
Food additives listed in Regulation (EC) No 1333/2008, and falling within codes E400 and E500, are used in the food industry for their gelling, thickening and stabilising properties. From a chemical point of view they are polysaccharides and are intentionally used as additives due to their ability to form a three-dimensional network that retains considerable amounts of water, hence improving the product’s consistency. The same additives are also utilised for their stabilising properties as a technological support in the production of flavourings for the meat industry. In this case, their presence in the end product is not indicated on the label.
The new histological method involves fixing the sample in formalin, dehydrating and embedding the sample in paraffin wax and the final process of microtome cutting into 4-5 µm sections. From each sample, 5 slides are made in order to sequentially perform 5 different colours to which different compositional elements are associated. Below are a few pictures of real examples.
Roast chicken with carrageenan, markedly blue colour on a colourless background;
Roast chicken with cellulose derivatives, pink colour on a green background representing proteins;
Cooked ham with starch, in black colour (left) using Lugol’s solution or pink colour (right) using PAS staining method;
Cooked ham without polysaccharides, green colour representing connective tissue and muscle fibres, and white colour representing adipose tissue.
This type of analysis is qualitative and the different possible measurands are indicated in Table 1. Those measurands can hardly be detected simultaneously if another analytical technique is used. This analysis does not provide the exact identification of a single specific substance. It indeed identifies, even in small traces, the presence of gelling agents, thickeners and stabilisers in meat-based products.
|POLYSACCHARIDES: GELLING AGENTS, THICKENERS AND STABILISERS|
|COO ACIDS||SO3 ACIDS||NEUTRAL|
|tragacanth E413||carrageenan E407||gum arabic E414|
|gum karaya E416||guar gum E412|
|pectins [non-amidated pectins E440(i)/amidated pectins E440(ii)]||locust bean gum E410|
|xanthan gum E415||Tara gum E417|
(alginic acid E400/sodium alginate E401/potassium alginate E402/ammonium alginate E403/calcium alginate E404; Propane-1‚2-diol alginate E405)
|gellan gum E418|
The analysis is also helpful to verify the correspondence between the ingredients indicated on the label and the actual composition of the products, and to perform a qualitative evaluation of the product.
The Laemmegroup Laboratory is the first in Italy to carry out this type of analysis.
For more information on this topic, please contact Chiara Mulasso –email@example.comSource: https://www.laemmegroup.it/en/2020/08/19/histology-for-detecting-gelling-agents-thickeners-and-stabilisers-in-meat-based-products/