Table 1 Constraints and optimization targets for the design of the “heart healthy breads”

 Cost per loaf (ingredient costs only)

$NZ1.50, $3.00

Set target values for baseline analyses (with the highest value still substantially less than commercial artisan bread loafs in the current NZ setting in the $NZ8 plus range).

 Total weight of dry ingredients

700-800 g

Makes around one kg of HHB loaf (given the addition of water to the recipe: see below).

 Active yeast mixture

3 to 4 tsp (12–16 g)

Basic requirement for bread design to ensure the bread rises, with 12 g for the HHB$1.5 loaf but slightly more (16 g) for the HHB$3 loaf given the increased weight of the seed ingredients.

 White or wholemeal flour

≥550 g

Set at 50 % each for white and wholemeal flour for the HHB$1.5 loaf; but at 25 % white and 75 % wholemeal for the HHB$3 loaf (to avoid excessive density and chewiness).

 Water

450 mls added to HHB$1.5 and 500 mls to HHB$3

Evaporation of the water during baking is a determinant of the final loaf weight.

 Total weight of added seeds/nuts

≤150 g

This was an arbitrary upper limit to constrain bread density and chewiness (especially relevant for older people and those with suboptimal dentition). Nevertheless, it is a level still below that found in some commercial breads e.g., one Finnish bread has 17 % seeds by weight (“Fazer Alku Jyväpala”). Ground linseed was used rather than whole linseed, given data on bioavailability and gastrointestinal tolerance [56].

 Sodium

<350 mg/100 g

Range for all the dry ingredients collectively (with a goal of <300 mg/100 g for the cooked loafs). The salt substitute with potassium chloride (KCl) was the preferred source of sodium (over normal salt) but was limited to a maximum of 1.5 tsp (9 g) per loaf to avoid any bitterness. The range of 250 to 300 mg/100 g in a final loaf would be substantially less than the mean level in 2013 in NZ (410 mg/100 g) [57] and for most breads in other high-income countries e.g., the USA [58].

 Alpha-linolenic acid (ALA)

Maximize

Maximized ahead of fiber and PUFA (first priority of the objective function).

 Dietary fiber

Maximize

Maximized ahead of PUFA (second priority of the objective function).

 Polyunsaturated fatty acids (PUFA)

Maximize

Maximized after maximizing fiber and ALA (third priority of the objective function).

 Potassium

Not specifically optimized

Given the use of a KCl containing salt-replacement, we focused on lowering sodium rather than increasing potassium.