key: cord-1041951-qqlfnjmy
authors: Corrado, Marina; Ahn-Jarvis, Jennifer H.; Fahy, Brendan; Savva, George M.; Edwards, Cathrina H.; Hazard, Brittany A.
title: Effect of high-amylose starch branching enzyme II wheat mutants on starch digestibility in bread, product quality, postprandial satiety and glycaemic response
date: 2022-01-26
journal: Food Funct
DOI: 10.1039/d1fo03085j
sha: 8788035375d397f0d8b1888f4ab609fa155c575f
doc_id: 1041951
cord_uid: qqlfnjmy

High-amylose starch branching enzyme II (sbeII) mutant wheat has potential to be low-glycaemic compared to conventional wheat; however, the effects of bread made from sbeII wheat flour on glycaemic response and product quality require investigation. We report the impact of white bread made from sbeII wheat flour on in vitro starch digestibility and product quality, and on postprandial glycaemia in vivo, compared to an isoglucidic wild-type (WT) control white bread. Starch in sbeII bread was ∼20% less susceptible to in vitro amylolysis leading to ∼15% lower glycaemic response measured in vivo, compared to the WT control bread, without major effects on bread appearance or texture, measured instrumentally. Despite the early termination of the in vivo intervention study due to the COVID-19 outbreak (n = 8 out of 19), results from this study indicate that sbeII wheat produces bread with lower starch digestibility than conventional white bread.

The two genotypes were each sown in eight 6 m 2 plots in a randomised block design in in April 2018. Yield and thousand grain weight (TGW) are reported in Table 2 as indication of grain performance when grown in the UK. Kernel weight was determined using a Marvin Seed Analyser (Marvitech GmbH) with a sample of approximately 300 grains per plot. The harvested grains were stored in the field trial station until October 2018, when they were milled into refined flour by Campden BRI using a Bühler mill. Means ± SEMs, n = 8. Mean ± SEMs, n = 4 bread rolls, 16 readings per bread roll (four on each roll side).

Parameter values that are significantly different in the sbeII bread compared to the WT control bread are indicated with an asterisk; *P < 0.05, **P < 0.01 and ***P < 0.001 (independent groups t-test). Triacylglycerol ( 

Sensory response to sbeII bread were compared to the WT control bread using a hedonic scale and 'Just-About-Right' (JAR) scale. The sensory evaluation was not carried out in parallel to accommodate the requirements of the randomized crossover study design.

Bread palatability was measured after each meal using a 9-point hedonic scale (1 = dislike extremely to 9 = like extremely) to determine overall likability, aroma, colour, flavour, moisture, and texture, as well as a JAR scale with five anchor points (1= much too weak to 5 = much too strong).

Two palatability questionnaires were completed after the intervention breakfast, one using a hedonic scale and one using a JAR scale. A 'penalty analysis' was used to determine which attributes of overall palatability (assessment of liking using hedonic scale) were not optimal or JAR, identifying attributes that were most detrimental to the product quality. The overall palatability scores (from the 9-point hedonic scale)

were ranked against the JAR scale responses 1 . The penalty score was calculated as , where 'JAR' is the

number of participants that indicated Just-About-Right and 'not-JAR' is the number of participants that indicated either too much or too little for the given attribute on the JAR scale. Any penalty scores greater than 1 indicated that improvement in the product palatability was needed.

The preliminary results on palatability did not reveal major differences in bread liking.

The sbeII bread scores for overall liking, aroma, flavour, sweetness, texture and size were above neutral on average (score = 5), as the WT control, however the sbeII bread appeared to be less moist than the WT control. JAR assessment suggested that participants perceived the sbeII bread as drier and doughier compared to the WT control but overall, it was reasonably 'acceptable' (Supplementary Figure 2) .

We explored palatability of sbeII bread which, according to the study cohort, was reasonably acceptable compared to the WT wheat control bread roll. The sensory characteristics and consumer acceptability of sbeII bread has not yet been rigorously tested and requires further investigation in a non-clinical setting. 

Use of just-about-right scales and penalty analysis to determine appropriate concentrations of stevia sweeteners for vanilla yogurt