Protein bars: protein sources and texture

A protein bar differs from an energy bar in one respect: protein is the main ingredient rather than a supporting one. That brings the two hardest questions in this category. Which protein source keeps the bar tasting good, and how do you stop it turning rock hard after a few weeks on the shelf? This piece covers the common sources, why texture is so difficult and what a good bar has to balance. It says nothing about health benefits, because that is not the job of a piece about formulation.

The common protein sources

Protein in a bar comes from two groups: refined protein powders and the protein already present in whole ingredients.

• Whey (from milk). Fairly neutral in flavour, dissolves well, gives a soft texture. It comes as concentrate (with some milk sugar and fat left in) and isolate (purer). The most common source of all.
• Casein (the milk protein left after whey is removed). Gives a denser, chewier body and is often paired with whey.
• Soy protein. Reasonably priced with good texture, but the bean note can show through unless it is handled carefully.
• Pea protein. The usual choice for dairy-free bars. Slightly earthy, often blended with rice protein to round it out.
• Rice protein. Light in flavour, a little gritty in quantity, rarely used alone.
• Peanuts and other nuts. Protein that comes with the whole ingredient, bringing fat and a roasted flavour with it. It cannot push the protein content as high as powders can, but it makes a bar taste good and keeps the ingredient list short.

Many bars on the market blend two or three sources. Whey for softness, casein for chew, nuts for flavour. The choice depends on what the bar wants to say on its label: dairy-free, plant-based, or simply good to eat.

Why texture is so hard

An energy bar forgives many mistakes because it has plenty of syrup, dried fruit and room to be soft. A protein bar does not. Three reasons:

First, protein powders draw in water. After the bar is pressed, moisture from the syrup and fats gradually migrates into the protein particles, the protein molecules bind more tightly to each other and the bar firms up. A bar that is soft in week one can be hard by month three. That is why every protein bar sample has to be stored for a few weeks before its texture is judged, rather than tasted fresh off the line.

Second, proportions. The more protein, the less room for syrup, fat and the other ingredients that make a bar soft, sweet and cohesive. The formulator is always caught between the two: raise the protein and lose softness, raise the softness and lose protein.

Third, flavour. Plant proteins carry an earthy or slightly bitter note, and whey at high levels has an aftertaste of its own. Masking with cacao or peanut is the familiar answer, but mask too heavily and every bar tastes the same.

Binders, sweetness and crunch

The binder is what holds a bar together: syrups such as rice syrup, glucose syrup or fibre syrups, working with fat from nut butter or oil. More syrup means a softer, sweeter bar. Less means a drier one that crumbles. Some recipes use sugar alcohols or soluble fibres to cut sugar while keeping the bar soft, but each option brings its own flavour and mouthfeel.

For crunch, some bars add protein crisps, small puffed pieces made from protein and starch, so the bar has some bite as well as softness. Roasted peanuts, oats and cashews do the same job in a more natural way.

What a good bar balances

We look at six things and try not to drop any of them:

• Protein content against flavour. The number on the label means nothing if nobody wants a second bar.
• Softness today against softness a few months from now.
• Moderate sweetness, so the protein is not hidden under sugar.
• A clean aftertaste.
• A readable ingredient list, with as few puzzling lines as possible.
• A sensible cost, because refined protein is expensive and every extra percentage point has a price.

How we work on PLAY Protein Bar

PLAY Protein Bar is the protein range among the four Color of Vietnam brands. Our method is still the small trial. Each round changes one or two things, say the binder ratio or the protein source, and our partner facilities press a small trial batch. The samples are split in two: half tasted at the next review session, half kept in the warehouse for a few weeks and tasted again.

At the second tasting the main question is texture: does the bar give when pressed, does it crumble when bitten, does it stick to the teeth. If it has clearly firmed up since the first tasting, we go back to the binder ratio and moisture before touching the protein source, because that is the cheaper place to fix it. Taste First, for us, means the protein number on the label has to come with a bar that people want to finish.

If you supply protein ingredients, or you are an R&D specialist who would like to work on this texture problem with us, get in touch or look at our open roles.