Assessing ingredient performance using the RVA 4800

The ability of the components of a product to withstand high-temperature processing conditions is of interest to formulators, who must balance the need for acceptable product rheology with safety and throughput. High-temperature processes are used in the manufacture of many food and industrial products.

RVA 4800

High-temperature processes are used in the manufacture of many food and industrial products. It is important for food processors to assess the performance (viscous potential and stability) of ingredients, to determine their suitability for formulations that are subjected to high temperature conditions required for sterilization and/or rapid processing including ultra-high temperature (UHT) processing, batch pressure cooking, retorting, jet-cooking and extrusion.

The RVA 4800 can perform regular tests below 100°C, as well as high-temperature tests up to 140°C in a specially designed pressure vessel. Several methods exploiting the high temperature capability of the RVA 4800 have been devised to assess ingredient performance of products that undergo extreme processing conditions.

Starch pasting behavior

The viscosity and pasting behavior of starch during the manufacturing process are affected by its chemical make-up and modifications, including those of resistant starches derived from retrograded high amylose types or cross-linked starches. The pasting behavior of these starches were easily assessed by the RVA 4800, with some starches requiring temperatures above 100°C to paste and gel. See application note here (RVA Method 45.01 Application Note).

Effect on polysaccharide thickeners

Pasteurization, blanching and sterilization are thermal processes that eliminate a desired number of microorganisms from food products. Enzymes, such as lipases, are also deactivated during these processes, thus increasing the shelf-life stability of the products. The severity of the thermal process determines the degree of pathogen removal. Improper calculation of thermal treatment requirements for retorted products can lead to spoilage risk, or to over-processing of the food that may result in loss of nutrients, impairment of rheological functionality and reduction of overall product quality. The RVA 4800 was used to mimic retorting conditions, and allowed assessment of the suitability and stability of polysaccharide thickeners in the formulation for high temperature processing. Highly cross-linked starches had greater thermal tolerance to retorting conditions. See application note here (RVA Method 46.01 Application Note).

Performance of hydrocolloid gums

Hydrocolloids are commonly used as thickeners and gelling agents in dairy, sauces and other food formulations. Some gums exhibit synergy with others, and are often used in combination to maximize their suitability for the particular process. Knowledge of the processing potential and stability of the gelling agent under various heat and shear conditions can aid formulators in ingredient choice for the intended process. The processing performance of various gums were assessed using a high-temperature, stepped-speed profile, giving information on viscosity and gel forming potential, and susceptibility to shear- and time-thinning, and thermal stability. Iota-carrageenan showed remarkable thermal tolerance, making it suitable for processes where back-pressure is an issue (eg. UHT dairy processing). See application note here (RVA Method 47.01 Application Note).

Starch suitability in steam jet cooking

Steam jet cooking is commonly used to prepare aqueous dispersions for food and non-food applications. This high temperature (generally in the range 110-140°C) and pressure process subjects the dispersion to high shear stresses, and results in disruption of the starch. A high-shear, high-temperature profile was used to mimic the jet-cooking process, to assess the processing potential of starches that are commonly used as fat replacers, gelling agents and stabilizers, and as paper wet end, size press and coating additives. Highly cross-linked starches showed enhanced resistance to high-temperature and high-shear processing conditions. See application note here (RVA Method 48.01 Application Note).