Australian Export Grains Innovation Centre

AEGIC is an initiative of the Western Australian State Government and Australia’s Grains Research and Development Corporation

Department ofAgriculture and Food

Evaluation of wheat fl our quality using MixoLab® and SRCJ. Ng1 and L. Cato1

1Australian Export Grains Innovation Centre (AEGIC), Perth, WA, 6151, Australia

1. INTRODUCTION 4. RESULTS AND DISCUSSION

3. MATERIALS AND METHOD

2. AIM

5. CONCLUSIONS

MixoLab® and the automated Solvent Retention Capacity (SRC) (Chopin Technologies, France) were used to characterise wheat varieties. MixoLab® was used to study dough rheological properties and starch gelatinisation of flour while SRC was used to study water absorption capacity, glutenin, pentosan and damaged starch functionality of flour.

A typical MixoLab® profile is shown in Fig. 1 showing C1 (water absorption); C2 (protein weakening); C3 (starch gelatinisation); C4 (hot gel stability) and C5 (starch retrogradation).

The MixoLab® profile of different flours used in baking and noodle trials is shown in Figs 2. In baking trials (Fig 2a), C2 measure of protein weakening as a function of mechanical work and temperature ranged from 0.35 to 0.54; C3 measure of starch gelatinisation ranged from 1.44 to 1.78; C4 measure of hot gel stability ranged from 1.14 to 1.73 while C5 measure of starch retrogradation in the cooling phase ranged from 1.91 to 2.80. The values of C3, C4 and C5 for WSN flour was higher compared to YAN flour. In addition the ‘cooking stability’ for WSN flour was also higher. This is consistent with earlier publication findings (Cato & Mills 2008) and related to the eating quality of noodles.

In this study (with the high sugar, high fat NtD baking method) no significant correlation between SRC lactic acid or sucrose and bread specific volume (BSV) was seen. This is probably due to the fact that many other factors contribute to the final bread volume including choices of processing method and equipment as well as ingredients (data not shown here).

Flour samplesA range of wheat varieties differing in protein content from 8.2 to 15.3% were evaluated. All samples were milled on a Buhler test mill and flour quality was tested using AACC International Approved Methods (AACCI, 2011).

MixoLab® and SRC Mixing and pasting behaviour of 100% wheat flour were analysed using the MixoLab® analyser. The MixoLab® measures (in real time) the torque (Nm) produced by the passage of dough between the kneading arms, allowing the study of physio-chemical behaviour. For the test protocol (Chopin+), 50g (adjusted for moisture content) of flour samples were placed in the MixoLab® analyser bowl and tested at optimum water addition. The mixing speed used was 73rpm. The settings used in the test were 8 minutes at 30°C with a temperature increase of 4°C/min until the mixture reached 90°C; at this point there is an 8 minute holding period at 90°C, after which the temperature was decreased at 4°C /min until it reached 55°C, followed by 6 minutes of holding at 55°C.

Four different solvents were used in SRC: deionised water, 50% sucrose, 5% sodium carbonate and 5% lactic acid.

The SRC testing was done in accordance to the AACC Approved Method 56-11. The test is based on the preferential solvation and swelling of the three polymeric, network-forming flour components by selected, material-specific solvents. The greater the swelling, and the greater the resistance of the swollen network to compression by centrifugation, the higher the solvent retention. The method enables the measurement of four key quality parameters of flour in one single test:

• Water absorption with the water SRC• Glutenin functionality with the lactic acid SRC• Pentosan functionality with the sucrose SRC• Damaged starch functionality with the sodium carbonate SRC

End products White Salted Noodles (WSN) were made from 100 parts of flour, water (32%) and salt (4%) using the Othake noodle machine. The final noodle thickness was 2.5mm. Yellow Alkaline Noodles (YAN) were made from flour, water (33%) and Kansai salt (2%) using the Othake noodle machine. The final noodle thickness was 1.4mm. Pan breads were baked using an AEGIC in-house method (reflecting typical SEA formulation, high in sugar and high in fat content). The loaves were baked using No time Dough (NtD).

The main aim of this investigation was to:

• characterise rheological and thermal properties of wheat flour • study suitability of wheat flour for a range of different products.

Both MixoLab® and SRC are useful tests in characterising flour properties. This study, supports previous findings on the relationship between MixoLab’s® starch properties (C3–C5) and the eating quality of noodles. In particular the sudden drop in consistency (between C3 and C4) is believed to be related to the swelling properties of starch. The characterisation of quality and functional properties of flour as determined by SRC is useful for defining differences between different wheat varieties. Further studies are required to understand the relationship of SRC and different baking systems as well as indicative end product quality.

References• American Association of Cereal Chemists International (AACCI). Approved Methods Committee. (2011). Approved methods of the American Association

of Cereal Chemists (11th ed.). St. Paul, Minn.: AACCI.• L. Cato and C. Mills (2008). Evaluation of the MixoLab® for assessment of flour quality. Food AUS, 60:12, 577-581.

Acknowledgements• Arnaud Dubat (CHOPIN Technologies), France, for his valuable advice and support.• Murdoch University for the loan of the MixoLab® for this study.• Grain Products Laboratory (AEGIC) for their help and support.

FIGURE 2 MixoLab® profiles for baking and noodle trials

FIGURE 1 Typical profile obtained from a MixoLab® test (Chopin Technologies)

FIGURE 3 SRC Summary

(a) Flour used in baking trials (b) Flour used in noodle trials

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