Today we have a shorter entry, but you can expand your knowledge with the article we propose at the end, which is open access and free.

Although all cereals, pseudocereals, and legumes that can be milled to obtain flour are seeds, in this section, we will discuss seeds that are usually incorporated whole into bread and baked products. These seeds have in common a high fat content. For this reason, it is difficult to obtain fine flours, although they can be ground more coarsely. However, flours from these seeds have a high risk of rancidity. Additionally, the sensory experience when consuming products with whole seeds is very different from that of consuming products with the incorporation of their flours. Therefore, it is more common to add these whole seeds, either in the dough or on the surface, of bread, biscuits, and other products.

Although the main reason for introducing these seeds may be sensory, these seeds also have interesting nutritional properties. As in other cases, there are no studies indicating the number of seeds we should consume to obtain certain nutritional benefits. And it seems clear that occasional consumption of some seed bread does not provide significant nutritional advantages. There is also some research suggesting that these benefits may be reduced if the seeds are consumed whole instead of as flour, due to lower bioavailability of beneficial substances. But their inclusion may be suitable in healthier diets. These seeds are of particular interest in gluten-free products, as they help mask strange flavours, generating flavours and sensations appreciated by consumers. Being whole, they release flavours inside the mouth when chewed, which does not happen in the case of flours. But it should be noted that this sensation depends on the type of seed.

Among the most commonly used oily seeds in baking products and savoury biscuits worldwide are sunflower, sesame, flaxseed, poppy, chia, and pumpkin seeds.

Nutritional aspects

All these seeds have a high-fat content, generally between 30 and 50%, but they mainly stand out for the quality of these fats. In all cases, the saturated fat content is very low, less than 7%, and monounsaturated and polyunsaturated fats stand out. Sesame has a high content of oleic acid, linoleic acid (omega-6) is present in sesame, sunflower, and poppy seeds, and linolenic acid (omega-3) is found in chia and flax seeds. These seeds also have a higher protein content than most cereals (between 15-20%), and a high fibre content. In the case of fibre, flaxseed and chia stand out, with a fibre content exceeding 25%. Regarding mineral content, these seeds have high levels of magnesium, phosphorus, and potassium (higher than wheat), as well as high calcium content in sesame, chia, and poppy seeds, and zinc in pumpkin seeds. All these seeds are also good sources of B-group vitamins and vitamin E, as well as antioxidants.

The nutritional benefits of consuming some of the nutrients present in significant amounts in these seeds have been demonstrated. Thus, the effects of high fibre or omega-3 fatty acid consumption are well known. Similarly, the consumption of lignans, a phytoestrogen with antioxidant activity present in significant amounts in sesame, flax, and pumpkin seeds, has demonstrated its anticancer activity. They also show a synergistic effect with vitamin E. Thus, vitamin E activity is increased in the presence of lignans, and their potential to reduce cholesterol is enhanced by the presence of vitamin E. Studies on the health benefits of consuming these seeds are more limited, but it is known that chia consumption can reduce the glycaemic index, increase satiety, reduce the risk of cardiovascular diseases and diabetes, among others. Likewise, flaxseed consumption has been associated with a reduction in cholesterol and the risk of cardiovascular diseases. In both cases, these benefits are associated with high levels of fibre and the type of fibre (mucilage with high thickening capacity). However, to achieve these effects, a large amount of bread enriched with a high quantity of these seeds would need to be consumed. But, in general, it is accepted that incorporating seeds helps to obtain healthier products with good sensory characteristics.

Table 1.: Nutritional content of some oilseeds (per 100g)

		Wheat	Sunflower	Flaxseed	Sesame	Chia	Pumpkin	Poppy seed
Nutrients	Moisture (g)	12.42	1.2	6.96	4.69	5.8	4.50	5.95
	Valor energético (kcal)	332	582	534	573	486	446	525
	Proteins (g)	9.61	19.33	18.29	17.73	16.54	18.55	17.99
	Lipids (g)	1.95	49.8	42.16	49.67	30.74	19.40	41.56
	Carbohydrates (g)	74.48	24.07	28.88	23.45	42.12	53.75	28.13
	Fibre (g)	13.1	9	27.3	11.8	34.4	18.4	19.5
	Sugars (g)	1.02	2,73	1.55	0,30	N	N	2.99
Minerals	Calcium (mg)	33	70	255	975	631	55	1438
	Iron (mg)	3.71	3.8	5.73	14.55	7.72	3.31	9.76
	Magnesium (mg)	117	129	392	351	335	262	347
	Phosphorous (mg)	323	1115	642	629	860	92	870
	Potassium (mg)	394	850	813	468	407	919	719
	Sodium (mg)	3	655	30	11	16	18	26
	Zinc (mg)	2.96	5.29	4.34	7.75	4.58	10.30	7.9
Vitamins	Vitamin C (mg)	0	1.40	0.6	0	1.6	0.3	1
	Tiamin (mg)	0.297	0.106	1.644	0.791	0.62	0.034	0.854
	Riboflavin (mg)	0.188	0,246	0.161	0.247	0.17	0.052	0.1
	Niacin (mg)	5.347	7.04	3.08	4.515	8.83	0.286	0.896
	Vitamin B6 (mg)	0.191	0.804	0.473	0.79	N	0.037	0.247
	Folates (µg)	28	237	87	97	49	9	82
	Vitamin E (mg)	0.53	26.1	0,31	0,25	0,50	N	1.77
Lípids	Saturated (g)		5.219	3.663	6.957	3.33	3.670	4.517
	Monounsaturated (g)		9.505	7.527	18.759	2.309	6.032	5.982
	18:1(g)		9.399	7.359	18.521	2.203	5.985	5.864
	Polyunsaturated (g)		32.884	28.73	21.773	23.665	8.844	28.569
	18:2(g)		32.782	5.903	21.375	5.835	8.759	28.295
	18:3(g)		0.069	22.813	0.376	17.830	0.077

The incorporation of these seeds in flour form reduces the strength of the dough, and stronger flours or reinforcing additives should be used. However, the use of seeds in the dough, especially on the surface, has a much smaller effect. The size of the seeds and cultural aspects should also be taken into account. Sunflower seeds, and especially pumpkin seeds, are very large, and it may be convenient to chop them slightly. On the other hand, poppy seeds, and especially chia seeds, are very small, and some people describe the experience of consuming these breads as somewhat gritty. In Spain, we are familiar with the consumption of sunflower and pumpkin seeds, and increasingly with flax and sesame seeds, closely linked to Mediterranean and Arab cuisine. However, other countries, such as those in Central and Northern Europe, have used poppy seeds to a greater extent. These customs can also influence the acceptability of the products. But there is a clear trend towards producing healthier bread with good sensory characteristics, and oily seeds can contribute to this purpose.

For more information:

De Lamo, B., Gómez, M. (2018) Bread enrichment with oilseeds. A review. Foods, 7, 191.