How the unuseful can be turned into sustainable and useful: novel potato protein bioplastics with unusual strength

In Southern Sweden the way potato starch is produced creates large amounts of by-product. This by-product consists of potato protein and non-edible compounds, which limits its use as food today. Improved uses of industrial by-product is of high interest for the future, and therefore finding a better use of the potato proteins from potato starch production is needed.Through this collaboration project between the researchers at SLU Alnarp and Lyckeby Starch AB it has been shown that potato proteins are suitable for making potato protein bioplastics. Also, the bioplastics made from these potato proteins have shown unusual strenght and stretchiness, properties that could be suitable for a multi-layered packaging bag for potato chips

Variation in protein composition of wheat flour and its relationship to dough mixing behaviour

Changes in extractability, amount and size distribution of polymeric proteins in the gluten of doughs during mixing were investigated. Ultracentrifugation was used as a non-destructive method to separate the gluten from the dough. Doughs prepared from commercial flour mixtures of different gluten strengths and mixed for varying periods, were analysed. Proteins were detected using RP- and SE-HPLC. The percentages of large unextractable polymeric protein (UPP), total UPP and large unextractable monomeric protein (UMP) were higher in the gluten phases of all flours at minimum and optimum mixing, compared to the flours. After overmixing, the percentages of large UPP, total UPP and large UMP in the gluten phases of the dough decreased to lower levels than in the flours. Differences in percentages of large UPP, total UPP and large UMP between gluten phases of different flours and mixing times originated from the genetic composition of flour proteins. The extractability of the glutenins in the flours reflected the quality of the specific flour. The protein extractability, especially of gliadins, was different in the gluten phase compared to in the flour. Ionic interactions seem to be important forces in the dough. (C) 2004 Elsevier Ltd. All rights reserved

The influence of dough mixing time on wheat protein composition and gluten quality for four commercial flour mixtures

The effect of mixing time on wheat protein composition and gluten formation was studied for three commercial flour mixtures (biscuit, standard and strong) and one durum flour. Ultracentrifugation was used to separate the fresh, wet gluten from the wheat-flour dough immediately after mixing. Small deformation dynamic theological measurements and RP- and SE-HPLC were used to determine the characteristics of the network formed, and the protein composition, respectively The gluten water content increased due to overmixing for most of the flours. However, no effect of mixing was observed for the storage modulus (G') of gluten for any of the flours. The value of G' of gluten was around 3, 3, 4 and 8 for Standard, Biscuit, Strong and Durum flour, respectively. Therefore, the increased water content during prolonged mixing was not related to the effect on G'. The strong flour resulted in the lowest G' for dough, a high G' for gluten and no increase in gluten water content with overmixing. The weaker standard flour resulted in the highest gluten water content, which increased considerably with mixing time. The durum flour did not show gluten development and breakdown similar to the other flours. The differences in large UPP, total UPP and large UMP between gluten from the different flours and mixing times originated from the genetic composition of flour proteins

Effect of mixing time on gluten recovered by ultracentrifugation studied by microscopy and rheological measurements

The effect of mixing time on gluten formation was studied for four commercial flour mixtures. The gluten phase was separated from dough using a nondestructive ultracentrifugation method. Small I deformation dynamic theological measurements and light and scanning electron microscopy were used. The recovered gluten was relatively pure with a small amount of starch granules embedded. The protein matrix observed by microscopy became smoother with prolonged mixing. No effect of overmixing was observed on the storage modulus (G') of gluten for any of the flours. The amount of water in gluten increased from optimum to over mixing for most of the flours. Increased water content during prolonged mixing was not related to an effect on G'. The Standard flour resulted in the highest water content of gluten, which increased considerably with mixing time. The Strong flour had the lowest G' of dough, a high G' of gluten, and no increase in gluten water content from optimum to overmixing. The Durum flour did not show gluten development and breakdown similar to the other flours. The differences in gluten protein network formation during dough mixing are genetically determined and depend on the flour type

Wheat glutenprotein structure and function: is there anything new under the sun?

This chapter focuses on wheat gluten protein and how its protein components, gliadin and glutenin, interact at the molecular level to produce structures, which contribute to particular functional properties. The aspects of gluten protein are highlighted in wheat gluten, in both, food and non-food products. Factors impacting wheat gluten protein chemistry and structure under various processing conditions and in different end-use products are discussed. The influence of the genetic make-up of wheat grain on the molecular structure and functional performance of gluten protein in the end-use products is discussed. The main factors steering wheat gluten protein structure-function relationships are thus summarised in the context of traditional and innovative applications