Application Finder

The determination of the oxidation stability of wine with the Rancimat is a newly developed method able to determine the antioxidant potential of wines. Different grapes as well as varied processing methods impart the color, taste, and anti-oxidative capacity for each wine blend or varietal. With the Rancimat and Polyethylene Glycol (PEG) methods, the antioxidant potential in different wines can be easily compared.The PEG method is used to compare the antioxidant capacity of different vintages and grape varieties. The induction time can be used as a quality criterion for different types of wine or different vintages. In this Application Note, the oxidation stability of different wines is determined in this way.

Processing degrades antioxidant levels in spices. The 892 Professional Rancimat determines oxidation stability with the PEG method as per AOCS Cd 12b-92 and ISO 6886.

Oxidation stability is an important parameter to assess the quality of animal feed. It provides information about the long-term resistance to degradation of the fatty acids, which can predict the storage stability of the product. Oxidation stability of many animal feeds can be directly and reproducibly measured by the Rancimat method, if polyethylene glycol (PEG) is used as the carrier material.No sample preparation is required for this application. This Application Note describes the determination of oxidation stability of fish food and dog treats. More information on the Rancimat method can be found on the Metrohm website.

Oxidation stability is an important parameter defining the quality of tea. It also provides information about the long-term stability of the naturally included antioxidants and thus the stability of the product. However, tea cannot be measured directly with the Rancimat method, as no evaluable induction time is obtained. The reason for this is that no measurable oxidation product is formed. However, using polyethylene glycol (PEG) as carrier material, many of these samples can be directly and reproducibly measured without any sample preparation. This is due to the antioxidants that are naturally present in the sample matrix, which stabilize the induction time of the PEG. The induction time can therefore be directly related to the oxidation stability of the sample.A reproducible and accurate determination of the oxidation stability is feasible using the 892 Professional Rancimat. In this Application Notes the oxidation stability of different teas is determined in this way. More information on the Rancimat method can be found on the Metrohm website.

The freshness as well as the smell and taste of coffee depend, among other things, on the content of antioxidants. The antioxidant content is critical to set a retail price and therefore it is of great interest for manufacturers and distributors to determine it. Classically, this parameter is determined via long-term storage tests. Oxidation stability offers a fast, alternative method, which can define the quality of coffee.Using the modified Rancimat method, the oxidation stability of coffee can be determined quickly and reliably. The sample is analyzed together with polyethylene glycol (PEG). The antioxidants present in the sample matrix stabilize the induction time of the PEG. The induction time can therefore be related directly to the oxidation stability and antioxidant content of the sample.This Application Note demonstrates the feasibility of the modified Rancimat method. Using the 892 Professional Rancimat, reproducible and accurate determination of the oxidation stability of different coffees is possible.

Some samples, such as cosmetics and food, cannot be measured directly with the Rancimat as no evaluable induction time is obtained. There are many reasons for this, for example a high water content, a too low fat content or various matrix effects. However, using polyethylene glycol (PEG) as carrier material, many of these samples can be directly and reproducibly measured without sample preparation. This is due to the antioxidants that are naturally present in the sample matrix, and which stabilize the induction time of the PEG. The induction time can therefore be directly related to the oxidation stability of the sample.Furthermore, with a standard addition it is possible to measure the content of antioxidants (AOC) such as vitamin E, vitamin C or an equivalent of it. The decrease of the antioxidants over time (for example, during storage of the sample) can thus be measured and evaluated. In addition, this method eliminates a costly sample preparation. A reproducible and accurate determination of the oxidation stability using the 892 Professional Rancimat can be realized.

The oxidation stability is an important factor for the quality of cosmetics. It also provides information about the long-term and storage stability of the product. Most cosmetic formulations cannot be measured directly with the Rancimat as no evaluable induction time is obtained. There are many reasons for this, for example a high water content, a too low fat content or various matrix effects. However, using polyethylene glycol (PEG) as carrier material, many of these samples can be directly and reproducibly measured without sample preparation. This is due to the antioxidants that are naturally present in the sample matrix, and which stabilize the induction time of the PEG. The induction time can therefore be directly related to the oxidation stability of the sample.In addition, this method eliminates a costly sample preparation. A reproducible and accurate determination of the oxidation stability using the 892 Professional Rancimat can be realized. In this Application Notes the oxidation stability of body care cream, moisturizer, body milk, body lotion, and toothpaste is determined in this way. More information on the Rancimat method can be found on the Metrohm website.

The Rancimat method determines the oxidation stability (OSI) and antioxidant capacity (SI) of solid foods. OSI measurements are performed directly, with extracted isolated fat, or via the polyethylene glycol method. SI can be determined when the sample is mixed with a reference of antioxidant-free fat.

This Application Note describes the determination of the oxidation stability of different sausages with the recommended method from Metrohm using an 892 Professional Rancimat.

This Application Note demonstrates the feasibility of the Rancimat method. Reproducible and accurate determination of the oxidation stability of flavored spirits is possible with the 892 Professional Rancimat.

Oxidation stability is an important quality criterion of chocolate as it provides information about the long-term stability of the product. Cocoa contains various flavonoids that act as antioxidants. The most important and common flavonoids are catechin, epicatechin, and procyanidin. Although the flavonoid content may vary amongst chocolate type, it can be said, the greater the cocoa content in the chocolate, the greater the antioxidant effect.Chocolate cannot be measured directly with the classical Rancimat method, as no evaluable induction time is obtained. There are many reasons for this, for example a too low fat content or various matrix effects. Traditionally, extraction of the fat from the chocolate using e.g., petroleum ether is therefore necessary.In this Application Note, the oxidation stability of white, milk and dark chocolate with varying cacao content is determined in without extraction. Instead, polyethylene glycol is used as conducting medium. More information on the Rancimat method can be found on the Metrohm website.

Higher antioxidant levels mean longer product viability. The 892 Professional Rancimat determines antioxidant content in many products using a linear regression method.

This document outlines Rancimat testing for both liquid and solid food samples, including direct and PEG methods, for oxidation stability QC in the food industry.