Report on collection of rules on use of recipe calculation procedures including the use of yield and retention factors for imputing nutrient values for composite foods

The use of "weight yield" (fat/water and alcohol) and "nutrient retention" factors is directly

related with recipe calculation procedures for composite foods. This way, the nutrient content

of prepared foods can be estimated from its individual ingredients for its publication in Food

Composition Databases (FCDB), labels and special diets. Missing values in analysed food

items can be calculated via these factors as well. Furthermore, because most foods are

consumed in a cooked or prepared form, the use of these factors is highly relevant for the

assessment of the nutrient intake of the population in nutrition surveys.
 

As already discussed in a previous report (Bell et al. 2006), analysing composite foods is

expensive and time consuming. Therefore, determination and appropriate use of nutrient

retention and weight yield factors for calculation of the nutrient content in prepared and/or

processed foods is an important task that should be addressed by FCDB compilers. Currently,

the use the factors available in the literature (e.g. Bognár; McCance & Widdowson; USDA) is

still a source of discrepancies among the European FCDB. This is not only a consequence of

the use of different sources of factors but also a result of inconsistent use of them.
 

An exhaustive literature review on degradation kinetics and nutrient retention in processed and

cooked foods has been carried out by Bergström (1994). This same work has provided a

collection of yield factors for foods and dishes used in Europe at that time. Recently, Bell et al.

(2006) have published an overview of the nutrient retention factors used by the European

FCDB, presenting information provided by 17 EuroFIR partners, such as source of factors used

and the availability of retention factor by nutrient. This work also illustrates the ranges of

values for nutrient retention being currently used, systematically arranged by food group.

However, as a result of the works mentioned above, it is evident that clear recommendations on

which factors should be applied, how and in which situation are still missing. 


The EuroFIR Compiler Network has decided unanimously during its first meeting (Paris,

March 2007), that to reach the goal of harmonising the recipe calculation procedure, the use

and selection of retention factors should follow consistent rules. This solution may sometimes

be at the expense of the accuracy of the data, but comparability of the values obtained by a

single calculation procedure is a compromise that all compilers have accepted, which is an

important step towards the harmonisation of the European FCDB. 

To date, the EuroFIR proposal for the harmonisation of recipe calculation procedures

(Reinivuo and Laitinen, April 2007) has been finalised, concluding the following:

- Weight yields should be applied at recipe level

- Nutrient retention factors should be applied at ingredient level.

Furthermore, due to the large variety of recipes available for each participating country, it has

been suggested that each compiler uses its own weight yield factors. However, compilers are

still committed to provide the values they have used together with some background

information, in order to fulfil the EuroFIR value documentation requirements.

The present work will focus on the use of the nutrient retention factors, which should be on the

line of the EuroFIR food classification and the cooking methods available in the LanguaL

thesaurus (Facet G). Additionally, a brief overview on weight yield factors, including

recommendations and calculation procedures will be discussed. Finally, examples on the use of

the factors and special cases on the calculation of recipes will be provided.

Respective factors are attached to this Deliverable for further application in European FCDBs.

Continuous quality improvements in FCDBs may however require a continuation of validating

and up-dating these values according to the latest state in science to ensure reliable calculation

of nutrient contents as composite foods develop further.