Prospects for the Use of the By-Products of Oil and Wine Production in Bakery and Confectionery Technologies ^†

Abstract

An influence of 1020% of wheat germ meal (WGM) and 15% of rosehip meal (RM) on the quality indicators and the nutritional value of rye–wheat bread was investigated. It was found that an addition of WGM in the entire range of dosages reduces the specific volume of the bread, and an addition of RM, on the contrary, increases this indicator. It is recommended to use 10% WGM with 5% RM to ensure the high quality and maximize the nutritional value of rye–wheat bread. An impact of 1525% of grape seed powder (GSP) on the quality indicators and nutritional value of butter biscuits was studied. It is recommended to add 20% GSP to obtain butter biscuits with improved quality and a high content of biologically active compounds.

1. Introduction

The use of secondary plant raw materials with high nutritional value in the bakery and confectionery technologies is an important area in the development of novel products, because it ensures the maximum usage of the natural potential of the feedstock. The analysis of literature sources shows the effectiveness of the use of grain for this purpose, as well as fruit and berry by-products, including the products of the processing of wine–grape pomace and the by-products of oil production [1,2,3,4,5,6,7].

The defatted meals of wheat germ (WGM) and rosehip (RM), which are by-products of the low-temperature CO₂ extraction of the corresponding oils, are interesting for the development of healthy products as a source of dietary fiber, polyphenols, vitamins E, B_1, PP, minerals potassium, calcium, magnesium, etc. [8]. Rosehip meal also contains ascorbic acid, which is used in baking as an oxidant improver to strengthen gluten and improve the structural and mechanical properties of the dough [9,10].

Large quantities of grape pomace are accumulated in the process of making wine. Grape seed powders extracted from the pomace of grapes grown in the southern regions of Ukraine are a rich source of health-promoting polyphenols, including hydroxybenzoic acids, stilbenes, flavonols, and flavanols. They contain dietary fiber, vitamins B₁, B₂, B₆, PP, minerals iron, calcium, potassium, and magnesium.

The purpose of the present research was to determine the influence of defatted wheat germ meal, rosehip meal and grape seed powder on the quality and nutritional value of bakery and confectionery products. Wheat germ and rosehip meals added alone or in combination were used in rye–wheat bread technology. Grape seed powder was chosen for butter biscuits technology.

2. Materials and Methods

2.1. Materials for Rye–Wheat Bread Making

Wheat germ meal (WGM) and rosehip meal (RM) were received from Scientific and Production LLC “Zhitomirbioproduct” (Ukraine). They were defatted dry powder by-products of the low-temperature CO₂ extraction of wheat germ and rosehip oils. The WGM and RM contained, respectively, 37.0 and 5.7 g/100 g of protein, 23.8 and 60.4 g/100 g of dietary fiber, 567.0 and 3850.0 mg GA/100 g DW of polyphenols, vitamins E (7.8 and 6.7 mg/100 g), B1 (2.1 and 1.2 mg/100 g), PP (2.4 and 1.8 mg/100 g), the minerals potassium (1200.0 and 3543.0 mg/100 g), calcium (115.0 and 336.8 mg/100 g), magnesium (220.0 and 813.3 mg/100 g), etc. RM contains 47.0 mg/100 g of ascorbic acid [8].

Commercial first grade wheat flour, hulled rye flour, salt, pressed baking yeast, and dry rye sourdough TM “Puratos Othello Norma” (Belgium) were also used for the study.

2.2. Materials for Butter Biscuits Making

Grape seed powder (GSP) was obtained from the grapeseed oilcake produced in LLC “Orion” TM “Oleo Vita” (Odesa, Ukraine). Considering its granulometric composition, grapeseed powder is fine-grained and homogenous: 80–82% of its fractional makeup consists of particles with dimensions between 20 and 30 μm. GSP contains 11.8 g/100 g of protein, 8.26 g/100 g of fat, 51.3 g/100 g of dietary fiber, 3344 mg/100 g (routine equivalent) of polyphenols, vitamins B₁ (0.2 mg/100 g), B₂ (0.54 mg/100 g), B₆ (0.21 mg/100 g), B₁₂ (5.67 mg/100 g), PP (3.33 mg/100 g), the minerals iron (20.09 mg/100 g), calcium (388.89 mg/100 g), magnesium (387.74 mg/100 g), potassium (1544.44 mg/100 g), phosphorus (325.37 mg/100 g), etc.

Wheat flour of the highest grade, powdered sugar, butter and hen’s eggs were used for the study as well.

2.3. Rye–Wheat Bread Making

The control bread formula consisted of rye flour (50 g), wheat flour (50 g), dry rye sourdough (2.5%, flour basis), salt (1.5%, flour basis), pressed yeast (2.0%, flour basis), and water (moisture content 47%). In experimental samples, 10-20% of the wheat germ meal or 2–6% of the rosehip meal or their combination was added instead of an equivalent amount of the rye and the wheat flour. Due to the high water absorption capacity of the additives (275 and 260%, respectively), the moisture content of the dough was increased by 1.0% relative to the control sample. The fermentation of all dough samples was carried out in a proofing cabinet for 90 min (W = 80 ± 5%, t = 30 ± 2 °C), after which the dough was divided into portions and formed, placed in the proofing cabinet (W = 80 ± 5%, t = 32 ± 2 °C), and baked at a temperature of 210 ± 10 °C within 25 ± 2 min using steam. All the breads were left at room temperature for three hours to be cooled.

2.4. Butter Biscuits Making

The basic recipe for butter biscuits was calculated based on 100 g of wheat flour, 24% powdered sugar, 78% butter, 6% hen’s eggs. The technology of butter biscuits includes the following stages: preparing an egg–sugar–butter emulsion; adding of wheat flour; kneading dough. In the experimental samples, 15–25% of grape seed powder was added instead of the equivalent amount of wheat flour.

3. Methods

Physicochemical indicators of bread and butter biscuits quality, such as the titratable acidity (bread only), wetting ability (biscuits only), moisture content, and specific volume were determined by standard methods.

4. Statistical Analysis

The experimental data are processed statistically by the Fischer–Student method at a reliability level of 0.95 with the use of the MS Office 2016 application package version, including MS Excel 2016. Research results were calculated as an average of at least three replicates.

5. Results and Discussion

1.

Determination of the influence of wheat germ and rosehip meal on the quality indicators and nutritive value of rye–wheat bread

The results of studies of the physical and chemical indicators of bread quality are presented in

Table 1. The effect of wheat germ meal (WGM) and rosehip meal (RM) on the total titratable acidity (TTA), specific volume, and moisture content of rye–wheat bread.

Bread Sample s	Dosage of Additives (%, Flour Basis)	TTA	Specific Volume (cm3/100 g)	Moisture (%)
Control	0	6.0	200	46.0
+WGM	10	6.5	185	46.7
	15	6.9	170	47.0
	20	7.3	150	47.6
+RM	1	6.4	215	46.4
	3	6.6	240	46.6
	5	7.4	255	47.0
+(WGM + RM)	10 + 5	7.6	195	47.7

.

It was found that an addition of 10–20% of WGM and 1–5% of RM increases the humidity of the bread, which is caused by the significant content of hydrophilic dietary fiber in the both additives and protein in WGM. Their TTA also increases by 8.3–21.7 and 6.7–16.7%, respectively. However, the meals have a different effect on the specific volume of the bread. In the case adding the wheat germ meal, this indicator decreases by 7.5–25.0% when compared to the sample without additives. This can be explained by the high activity of enzymatic processes, primarily proteolysis, under the action of glutathione, which is contained in the wheat germ [9]. This makes the use of more than 10% of wheat germ in the technology of rye–wheat bread inappropriate. The introduction of RM, on the contrary, leads to an improvement in the specific volume of bread by 7.5–27.5% due to the strengthening of wheat flour gluten under the action of ascorbic acid contained in the RM.

The combined use of meals in the experimental dosage (10%WGM + 5%RM) almost eliminated the negative impact of WGM on the specific volume of bread, bringing this indicator closer to control sample. When compared with samples containing a separate application of 10.0% WGP, the specific volume of this bread increased by 11.0%. In our opinion, this is associated with a decrease in the activity of proteolysis in the dough in the presence of RM.

The addition of both meals in selected dosages significantly increased the content of physiologically functional ingredients in bread (

Table 2. The effect of wheat germ meal (WGM) and rosehip meal (RM) on the nutritive value of rye–wheat bread.

Nutrients	Control Sample	Bread with Additives (10% WGM +5% RM)
Protein, g	6.40	7.30
Fiber, g	5.20	8.90
Minerals, mg
K	11.10	26.60
Ca	2.00	2.90
Mg	3.50	7.70
P	10.30	11.80
Fe	0.80	3.30
Vitamins, mg
B1	0.18	1.10
PP	0.90	1.10
E	1.30	1.60
Polyphenols, mg	90.00	221.50

).

The results presented in Table 2 show that the addition of 10% WGM along with 5% RM to rye–wheat dough resulted in increase in protein content by 14.1%, and dietary fiber by 71.2%. The content of potassium was 2.6 times greater, magnesium—2.0 times, iron—3.1 times, vitamin B₁—6.1 times, vitamins PP and E—22.0 and 23.0% higher, respectively, in the experimental sample of bread than in the control. It was noted that due to the addition of meals, the content of polyphenols in bread increased by 14.6 times.

2.

Determination of the influence of grape seed powder on the quality indicators and nutritive value of butter biscuits

The results of the study of physicochemical parameters of the quality of butter biscuits with grape seed powder are shown in

Table 3. The effect of grape seed powder on the quality of butter biscuits.

Dosage of Powder (%, Flour Basis)	Wetting Ability, %	Specific Volume (cm3/100 g)	Moisture (%)
0	150.0	178	5.5
15	148.0	176	5.5
20	146.0	172	5.6
25	137.0	165	5.7

.

It was found that an addition of 15–20% of the powder reduces the specific volume of biscuits by 1.1–3.4 % and the wetting ability by 1.3–2.7%; an addition of 25% of GSP reduces the specific volume of biscuits by 7.3% and the wetting ability by 6.7% when compared to the control sample. So, an addition of the grape seed powder to the butter biscuit is advisable in an amount of up to 20% of the weight of the flour, since an increase in an amount of powder up to 25% degrades the quality indices.

The addition of GSP increases the content of nutrients and biologically active ingredients in butter biscuits (

Table 4. The effect of grape seed powder on the nutritive value of butter biscuits.

Nutrients	Control Sample	Butter Biscuits with 20% GSP
Protein, g	7.06	7.30
Fiber, g	0.06	6.24
Minerals, mg
K	89.19	216.35
Ca	22.58	54.70
Mg	10.99	45.16
P	68.33	87.36
Fe	0.86	3.86
Vitamins, mg
B6	0.02	0.04
PP	0.84	1.74
Polyphenols, mg	00.00	647.35

).

The results presented in Table 4 show that the addition of 20% GSP to butter biscuits significantly increases the content of dietary fiber, potassium, and calcium by 2.4 times, phosphorus—1.3 times, iron—4.5 times, vitamin B₆—1.5 times, vitamin PP—2.4 times. In addition, a sample of butter biscuits with GSP contains 647.35 mg of polyphenols, while traditional biscuits do not.

6. Conclusions

The results of this study indicated that wheat germ meal and rosehip meal are promising additives for the production of rye–wheat bread with a high content of protein, dietary fiber, vitamins, polyphenols, and minerals. The introduction of more than 10% wheat germ meal leads to a significant deterioration in the specific volume of bread, probably due to active proteolysis in the dough. The introduction of rosehip meal in the entire dosage range improves the quality of the bread due to the strengthening of wheat gluten. To ensure high quality and maximize the nutritional value of rye–wheat bread, it is recommended to use 10% of wheat germ meal in complex with 5% rosehip meal.

Grape seed powder can be considered a promising additive in butter biscuit technology as a source of polyphenols, dietary fiber, vitamins, and minerals. The addition of up to 20% of the powder improves the physical–chemical indicators, such as the specific volume and wetting ability, as well as increases the nutritional value of butter biscuits.