Better Organic Bread: Integrating raw material and process requirements for organic bread production

Abstract

This project aimed to develop agronomic strategies and optimise milling and baking processes which enable more UK produced organic wheat to be used for breadmaking. Spring wheat trials were established on three organic farms in England from 2006 to 2009 inclusive, to evaluate variety and fertility management treatments: type and rate of manure/compost application, rhizobial inoculation of pre-crop clover to influence N-fixation/supply, and targeted micronutrient supplementation to enhance grain selenium levels. Yield, agronomic and disease assessments were supplemented with evaluation of bread making performance of the wheat samples. Results indicate that variety choice is a pre-requisite for achieving milling grade and that spring varieties Paragon, Tybalt, Granary, Fasan and Amaretto can produce adequate protein levels in different regions. Composted farm yard manure (cattle) and composted green waste applications can increase yield significantly (p < 0.0001) by up to 0.5 t/ha where lower fertility conditions exist. However, where rotations maintain adequate fertility and a two year grass/clover ley precedes spring wheat, significant yield benefits from these composts are unlikely. Applications of composted chicken manure permitted by organic farming standards significantly (p < 0.0001) increased yield by up to 0.5t/ha only at sites with lower soil fertility. Grain protein content was increased significantly by up to 1%. Milling and baking trials showed that loaf volume was not increased by variety choice, farm yard manure and green waste compost treatments, but chicken manure compost increased loaf volume by 3%. However, the cost benefit of using this type of organic fertiliser is dependent on the input cost of such products and an adequate premium for milling grade organic wheat.

The use of microbial inoculants to enhance nitrogen fixation by preceding clover crops coupled with compost application to improve soil N retention provided some significant (p < 0.05) yield benefits (0.79t/ha) on land recently converted to organic production in spring wheat in a preliminary trial harvested in 2005. However, in more extensive trials of similar treatments on the three organic farms in 2008 and 2009, no increase in spring wheat yield or protein content due to inoculation of the preceding clover was observed. The food industry partners evaluated selected milling and baking approaches using test and plant bakery conditions. This showed that protein supplementation and dough recipe modification can result in wholemeal loaves of acceptable quality from commercial samples of UK grown organic Paragon, Amaretto and Tybalt.