Flavor Characteristics in Raw and Roasted Walnuts

Loaves containing walnuts are chosen for their robust rich, flavor, as well as by the consumer who is making healthier choices.  The debate over whether to pre-roast walnuts before adding them to the dough continues...

An informal panel of experienced tasters compared the differences between loaves prepared under the same parameters, except one dough had raw walnuts and one had roasted walnuts.

 

The appealing taste of walnuts has long been popular in Europe and the US. Their flavor is agreeable without the addition of sugar. Recent studies showing that walnuts reduce cholesterol in the body are another reason walnut products are successful in Europe, North America and more recently, Japan. Now firmly established in Tokyo, this trend is spreading throughout Japan with most  metropolitan bakeries offering at least 3 or 4 varieties of walnut loaves.

The flavor of walnuts stands well on its own; a walnut loaf does not need butter to enhance its flavor or make it appealing. This very much appreciated in the U.S. where walnut breads are served alone, and in France, where they are served either alone or as an accompaniment to cheese.

At a seminar on walnuts in bakery products, it was very interesting to me to learn, during discussions with Japanese bakers, of the common practice of roasting the walnuts before adding them to the dough mixture. This technique is little used in North America and not common in Europe.

Sponsored by the California Walnut Commission and Nippon Flour Mills, the four seminars were held at NFM facilities in Tokyo, Kobe, Fukuoka and Nagoya. Mr. Sasaki, of NFM Fukuoka staff, kindly prepared 2 doughs for me, using raw walnuts in one and pre-roasted walnuts (from the same shipment) in the other.

Formula:

Flour, N-Napoleon 100% (unbleached, non-bromated bread flour)

Sugar, granulated, 3%

Salt, 2%

Malt syrup, 0.5%

Dry instant yeast, 1%

BBJ (yeast food), 0.2%

Water, 65%

Walnuts: 1st trial: roasted and cooled, 35%

Walnuts: 2nd trial: raw, 35%

Mix, fermentation and bake conditions (time, temperatures and RH) were identical for both doughs. Although our test bakes were on a formula with 3% sugar, the walnut lends its flavor well to a loaf without any sugar.

An informal tasting by the CWC and NFM staffs gave the following results:

-Flavor of loaf

All participants found a more intense flavor in the loaf made from raw walnuts. The walnut flavor in the loaf made from roasted walnuts was more subtle, light and less clearly identifiable as ‘walnut’. (This suggests that a greater quantity of walnuts would be required to maintain an identity with walnut’s characteristic flavor.)

-Flavor of crumb

All tasters found that the walnut flavor in the ‘raw’ nut dough had been incorporated into the dough itself: the crumb of the loaf was walnut flavored! That made it a distinctly different product than a loaf containing walnuts.

-Aroma

Most participants detected a stronger nutty aroma in the loaf made from roasted nuts.

-Flavor characteristics

Some participants detected a slight bitter taste in the loaf from roasted walnuts. Several noted a sweetness in the raw nut loaf.

-Texture

Tasted apart from the crumb of the bread, the ‘raw’ nuts, after baking, had slightly more resistance to the bite. When tasted as part of the loaf, however, the difference was less noticeable, with the ‘raw’ walnut loaf being slightly more crunchy.

-Color

The characteristic ‘burgundy’ was present in the loaves made from 'raw' nuts.

The color of a walnut loaf was less pronounced in the ‘roasted’ loaves.

It would appear that using roasted walnuts in a bread dough would not be in the interests of the baker either for reason of flavor or economy. All of the tasters noted a decrease in flavor with the roasted nuts as well as the fact that the nuts lost their ability to contribute their flavor to the dough itself.