Scholarly article on topic 'Basic Physical-Chemical and Sensorial Evaluation of Some Fermented Mashes Produced from Wheat, Husked Millet, Barley Malt and Oat'

Basic Physical-Chemical and Sensorial Evaluation of Some Fermented Mashes Produced from Wheat, Husked Millet, Barley Malt and Oat Academic research paper on "Agriculture, forestry, and fisheries"

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Abstract of research paper on Agriculture, forestry, and fisheries, author of scientific article — M.-L. Pacala, L. Oprean, O. Tita, L. Brudiu, M. Begea, et al.

Abstract Fermented mashes based on different cereal grist are a healthy and nutritious beverage, a source for new functional products with beneficial effects on human health. These mashes are a thick consistency and sour-sweet taste, different colors depending on the ingredients and method of preparation. In this study were determined the main physical and chemical characteristics (pH, volatile and total acidity, total and soluble dry substances, alcohol concentration, dynamic viscosity) and was made sensorial analysis of some boiled aqueous mashes obtained from wheat, husked millet, barley malt and oat. Mashes were fermented at 30°C with a mixed culture of mesophilic cheese lactic acid bacteria and wheat beer yeast for 23h, followed by a cold maturation at 4°C for 42h. This study allows exploring the potential of different cereals to produce cereal-based beverages. The best results were obtained for mashes containing a larger amount of barley malt, followed by mashes with oat. Highest dynamic viscosities were recorded for mashes obtained only from wheat and millet. All determinations were made in triplicate and data were shown as mean ± SD.

Academic research paper on topic "Basic Physical-Chemical and Sensorial Evaluation of Some Fermented Mashes Produced from Wheat, Husked Millet, Barley Malt and Oat"

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Engineering

Procedía

ELSEVIER

Procedía Engineering 42 (2012) 222 - 231

www.elsevier.com/locate/procedia

20th International Congress of Chemical and Process Engineering CHISA 2012 25 - 29 August 2012, Prague, Czech Republic

Basic physical-chemical and sensorial evaluation of some fermented mashes produced from wheat, husked millet, barley

malt and oat

M.-L. Pacala33*, L. Oprean3, O. Titaa, L. Brudiub, M. Begeac, A. Sirbud

aLucian Blaga University ofSibiu, Dep. Agricultural Science and Foodlndustry, 7-9Dr. I. Ratiu St., 550012 Sibiu, Romania bS.C. VIO-MARPRESTS.R.L., Dep. Quality Management, 900581 Constanta, Romania institute ofFood Research, Bucharest, 202 Splaiul Independentei S6, Romania dConstantin Brâncoveanu University ofRâmnicu-Vâlcea, Dep. Technical andEconomical, Romania

Fermented mashes based on different cereal grist are a healthy and nutritious beverage, a source for new functional products with beneficial effects on human health. These mashes are a thick consistency and sour-sweet taste, different colors depending on the ingredients and method of preparation. In this study were determined the main physical and chemical characteristics (pH, volatile and total acidity, total and soluble dry substances, alcohol concentration, dynamic viscosity) and was made sensorial analysis of some boiled aqueous mashes obtained from wheat, husked millet, barley malt and oat. Mashes were fermented at 30 °C with a mixed culture of mesophilic cheese lactic acid bacteria and wheat beer yeast for 23 h, followed by a cold maturation at 4 °C for 42 h. This study allows exploring the potential of different cereals to produce cereal-based beverages. The best results were obtained for mashes containing a larger amount of barley malt, followed by mashes with oat. Highest dynamic viscosities were recorded for mashes obtained only from wheat and millet. All determinations were made in triplicate and data were shown as mean ± SD.

©2012 Published by Elsevier Ltd. Selection under responsibility of the Congress Scientific Committee (Petr Kluson)

Keywords: Cereal mashes; fermentation; wheat; millet; barley malt; oat

a* Corresponding author. Tel.: +407-018-5438; fax: +4-026-921-2558. E-mail address', mariana.pacala@yahoo.com.

Abstract

1877-7058 © 2012 Published by Elsevier Ltd. doi:10.1016/j.proeng.2012.07.410

1. Introduction

Now, growing consumer concern for food as healthy, based on correct food nutrition principles. Fermented mashes based on different cereal grists (CGMs - Cereal Grist Mashes), namely braga in Romanian, is a healthy and nutritious beverage, a source for new functional products with beneficial effects on human health [1,2,3]. Braga is a pleasant traditional fermented beverage in Balkan region with a thick consistency and sour-sweet taste, depending on the ingredients and method of preparation [2,4]. Consequently, justified concern for the study to obtain such products based on cereals, which are not yet valued to the level where it should [5,6,7]. The objective of this research was to study the influence of cereal type used to obtain of some fermented mashes in specified technological conditions on the main physical-chemical and sensorial characteristics of fermented mashes. This study allows exploring the potential of different cereals to produce cereal-based products with very good sensorial characteristics.

2. Materials and methods

2.1. Preparation of cereal-based fermented mashes

2.1.1. Preparation of sweet cereal mashes

Fermented mashes based on whole wheat, barley malt, oat and husked millet were obtained based on general technological diagram of operations described by [2,4]. Main characteristics of cereals used in this research were: Spelt wheat (Triticum spelta, humidity: 10.6%, proteins:12%, lipids: 2.8%, carbohydrates: 62%, fibres: 8.8%) from S.C. Solaris Plant SRL, Bucharest, Romania, country of origin: Romania, Proso millet {Panicum miliaceum, humidity: 12.1%, proteins: 11%, lipids: 3.9%, carbohydrates: 70.6%, fibres: 1%) as husked white millet from S.C. Sano Vita SRL, Rm. Valcea, Romania, country of origin: Ukraine and oat (Avena sativa, humidity: 11.8%, proteins: 16.9 %, lipids: 6.9%, carbohydrates: 71.2%, fibres: 10%) from S.C. Solaris Plant SRL, Bucharest, Romania, country of origin: Romania. Barley malt (Pilsner barley malt (well modified), humidity: 5.2%, proteins: 10.8 %, lipids: 3%, yield: 81.6%, fibres: 4.5 %, colour: 3 EBC), from Weyermann Specialty Malting is also used in the fabrication recipe of mashes.

Grain grinding was done with a laboratory mill (Buhler's Universal Laboratory Disc Mill, type DLFU) with the distance between the disks set to 0.4 mm for wheat, barley malt and oat and for husked millet to 0.05 mm. Analysis of ground products was made with a Retsch\ Laboratory Vibratory Sieve Shaker, AS 200 basic set at amplitude of 2,5 mm and time of 10 min. Data of the sieve set was 1.25 mm, 0.630 mm, 0.400 mm, 0.315 mm, 0.250 mm and 0.160 mm. The particle size distribution of the grist used to obtain of mashes is shown in Table 1.

Six mashes (Mi, i=l,6) were made with the initial ratio of 1:12 between the amount of grist (10 parts) and water (with hardness less than 5°dH). The ratio between of grist quantities (whole wheat, [g] : husked millet, [g] : barley malt, [g] : oat, [g]) used for each mashes were: Ml - 3:3:3:1; M2 - 3:3:1:3; M3 -4:3:3:0; M4 - 4:3:0:3; M5 - 6:4:0:0; M6 - 5:5:0:0.

The mashes boiling was done in a 2000 mL Erlenmeyer beakers under heating plate with magnetic stirrer IKA RH basic 2 {IKA WERKE GmbH) for a constant mixing and in all volume of mashes. Boiling duration was 2 h and hot water was added several times until the end of the boiling process.

Boiled mashes were cooled at 30 Con water bath, under continuous agitation, in time (15 - 20) min. and their content was diluted with water to 1:12, the initial ratio, homogenized and subjected to coarse filtration, by press, using a metal sieve with holes of 0.63 mm size. Coarse filtration is recommended for the production of cereal-based products braga types, which are characterized by a high content of particles in suspension. After filtering operation was obtain filtered mashes and spent grains.

M.-L. Pacala et al. / Procedía Engineering 42 (2012) 222 - 231 Table 1. The particle size distribution of the Spelta wheat, Proso millet, Pilsner barley malt and oat grists

Number of sieve Mesh width (mm) Material on sieve (% w/w)

(separated fractions'

Spelta wheat Proso millet Pilsner Barley malt Oat

1 (Husks) 1.250 9.00 0.00 4.18 19.60

2(Coarse grists I) 0.630 38.92 0.78 38.05 37.20

3(Coarse grists II) 0.400 23.95 13.79 25.90 13.40

4(Fine grists I) 0.315 6.79 19.80 7.77 5.60

5(Fine grists II) 0.250 4.79 23.50 5.18 6.80

6(Fine grists III) 0.160 5.99 25.83 6.77 9.80

Bottom (Flour) - 10.58 16.30 12.15 7.60

Then for each filtered mashes is added 7% w/w white crystalline sugar (purity: minimum 99.8% dry matter; humidity: maximum 0.06%) as a source of sugars for alcoholic and lactic acid fermentation. Mashes were homogenized for complete dissolution of sugar crystals. This provides sweet mashes. In Table 2 were briefly characterized unfiltered, filtered and sweet mashes.

Table 2. Main physical-chemical characteristics of unfiltered, filtered and sweet mashes

Unfiltered mashes

Filtered mashes

Sweet mashes

Code mash Total dry substance (%) D.M.t, pH Total acidity' (% w/w) AT±SDxl03 Dynamic viscosity (CP) TI Total dry substance (%) D.M.t, PH. Dynamic viscosity (CP) TI

Ml 6.23 ± 0.12 6.12 ± 0.15 0.037 ± 0.90 26.6 ± 0.50 12.21 ± 0.25 6.05 ±0.11 26.6 ± 0.61

M2 7.16 ± 0.17 5.98 ± 0.12 0.045 ± 0.85 48.8 ± 1.02 12.86 ± 0.33 5.90 ±0.09 47.7±1.23

M3 7.26 ± 0.19 5.90 ± 0.11 0.048 ± 0.86 23.3 ± 0.50 11.53±0.24 5.83 ±0.11 25.5i0.53

M4 6.89 ± 0.15 6.09 ± 0.13 0.041 ± 0.95 27.8 ± 0.53 12.73 ± 0.24 5.97 ±0.13 27.8i0.52

M5 6.77 ± 0.14 5.98 ± 0.13 0.049 ± 0.97 772.6 ± 13.83 12.02 ± 0.24 5.89 ± 0.12 700.4 i 14.22

M6 6.89 ± 0.14 6.09 ± 0.12 0.046 ± 1.18 1038.0 ± 20.45 12.93 ± 0.23 6.08 ± 0.15 1010Ü8.08

Note: mean values of triplicate determinations (n=3) ± standard deviation and significant differences a=0.05 * - expressed as lactic acid (g lactic acid / 100 g of mash); ** - expressed as acetic acid (g acetic acid / 100 g of mash). 1 cP = 0.001 Paxs = 1 mPaxs

2.1.2. Fermentaionprocedure

Series of sweet mashes was inoculated (each mash) with a mixed culture of yeast (0,0117% w/w; Safale wb-06 - dry wheat beer yeast from Fermentis, Division of S.l.Lesaffre, France; manufactured in Belgium) and special lactic acid bacteria (0,0367% w/w); Lactoferm - dry cheese culture from Brouwland, Belgium), incubated at 30 °C for 23 h in the thermostat and then stored at 4°C for 42 h in the refrigerator. At beginning of fermentation and after 17, 23, 41, 47 and 65 h of follow-up fermentation the mashes were analyzed (pH, volatile and total acidity, total and soluble dry substances, alcohol concentration, dynamic viscosity) (Table 3). At the end of fermentation (after of 65 h) was done sensory evaluation of fermented cereal-based mashes.

2.2. Physical-chemical analysis of cereal-based fermented mashes

2.2.1.pH

The pH was determined using a pH-meter Orion 2 STAR {Thermo Electron Corporation, Ltd.) with calibration in 2 points. Before mash samples were thermostated at 20 °C.

2.2.2. Totalacidity

Total acidity was determined by titrating samples to be analyzed with sodium hydroxide solution 0.1 N, in the presence of bromothymol blue indicator, alkaline solution 4%o, using a microburettes. Total acidity is expressed in g lactic acid per 100 g of mash (% w/w expressed as lactic acid).

2.2.3.Alcoholic concentration

Alcoholic concentration (A, % w/w) of fermented mashes was determined by analyzing for a same their corresponding distillates, using direct method with the Alkotest Analyzer alcoholtest {Bulteh 2000, Ltd); if a volatile acidity of distillate is maximum of 0.1 g acetic acid /100 mL of distillate. Distillate was obtainedusing,Rqy^a's (R. Espinar, S.L.) the semiautomatic distillerAlcotest-1 with steam-drive.

2.2.4. Volatileacidity

Volatile acidity (A„) was determined by titrating distillates using a microburettes with sodium hydroxide solution 0.1 N in the presence of bromothymol blue indicator, alkaline solution 4%o. Volatile acidity is expressed in g acetic acid per 100gof fermented mash (% w/w expressed as acetic acid).

2.2.5. Dynamic viscosity

Dynamic viscosity was determined at 20 °C using a Yield Stress Rheometer YR-1 Brookfield {Brookfield Engineering Labs., Inc.) on mode for calibration, equipped with a spindle S72 at 100 RPM. Enough sample in a 200 mL Berzelius beaker was use to immerse the spindle and to analyze a homogeneous sample of fermented mash. Temperature was maintained using a circulating water bath refrigerated Brookfield TC-502 {BrookfieldEngineeringLabs., Inc.).

2.2.6. Total and soluble dry substance

Total dry substance (% w/w) was determined at 105 °C with a Moisture Analyzer tip ML-50 (A&D Instruments, Ltd.) with a halogen lamp; first samples were kept in oven at 40 °C for 30 min. for pre-drying.

Soluble dry substance (% w/w) was determinate at 20 °C with the DMA 35 Portable Density Meter {Anton Paar GmbH). For that fermented mash samples were centrifuged at 8500 RPM for 10 min. and used the supernatant.

2.3. Sensorial evaluation

The sensorial evaluation of the cereal fermented mashes was performed by 17 assessors, highly trained for this analysis, which, normally, know about this fermented products based on cereal (considered as reference standards). They consume these products sometimes. Assessors are ages between 25 and 35 years and were instructed to cleanse the palate between each sample with the drinking water.

To evaluate the acceptability and identify the favourite product we used a simple hedonic descriptive test for evaluating the next attributes: appearance, stability, taste, texture, flavour and consistency of samples by according 5 points for very pleasant to 0 point for unpleasant; between these 1 point for just evidenced, 2 point for slight, 3 point for moderate and 4 point for pleasant. The results were presented in a spider web diagram.

2.4. Statistical analysis

All determinations were made in triplicate and data were shown as mean ± SD. In order to study significant differences between the different sampling points during the fermentation process a variance analysis was performed, with a confidence interval of 95% (p<0.05).

3. Results and discussions

3.1. Physical-chemical analysis of fermented cereal-based mashes

The main chemical and physical characteristics of the six studied based on cereals mashes during the 65 h of the fermentations were given in Table 3.

From experimental data centralized in Table 2 was observed that oat grists determine the increase of dynamic viscosity of mashes (the M2 mash was compared with Ml mash and the M4 mash was compared with the M3 mash) [4,9].

Increased viscosity is higher when the mash does not contain a larger proportion of Pilsner barley malt grist (the case of the M2 mash), which is a source of various hydrolytic enzymes.

Table 3. The main chemical and physical characteristics of mashes at different times of get their.

Total Volatile Alcoholic Dynamic Total dry Soluble dry

Time (h) acidity' acidity6 concentration viscosity substance substance

(ti; i=l,6) pn (% w/w) (% w/w) (% w/w) (CP) (%) (%)

AT±SDxl03 Av±SDxl03 A± SDxlO3 ri D.M.t, D.M.s,

Ml Mash

ti;0 6.05 ± 0.11 0.036 ± 0.73 0.0000 ± 0.00 0.00±0.00 26.6 ± 0.61 12.21 ± 0.25 11.10 ± 0.28

t2; 17 3.71 ± 0.06 0.152 ± 3.31 0.0096 ± 0.17 0.72 ± 12.85 25.5 ± 0.47 11.36 ± 0.20 10.80 ± 0.19

t3;23 3.54 ± 0.06 0.179 ± 3.45 0.0118 ± 0.22 1.04 ± 19.58 24.4 ± 0.48 10.78 ± 0.20 10.10 ± 0.23

t4; 41 3.58 ± 0.07 0.183 ± 3.64 0.0135 ± 0.15 1.14 ± 15.48 26.6 ± 0.49 10.52 ± 0.21 9.80 ± 0.20

t5;47 3.54 ± 0.05 0.196 ± 4.09 0.0142 ± 0.27 1.24 ± 23.24 30.0 ± 0.50 10.31 ± 0.19 9.60 ± 0.18

t«; 65 3.54 ± 0.05 0.190 ± 4.01 0.0076 ± 0.18 1.29 ± 27.46 28.9 ± 0.73 10.73 ± 0.26 9.70 ± 0.24

M2 Mash

ti;0 5.90 ± 0.09 0.049 ± 0.92 0.0000 ± 0.00 0.00±0.00 47.7 ± 1.23 12.86 ± 0.33 10.50 ± 0.27

t2; 17 3.40 ± 0.04 0.240 ± 4.44 0.0122 ± 0.24 0.59 ± 11.54 45.5 ± 0.90 11.63 ± 0.23 10.00 ± 0.20

t3;23 3.22 ± 0.06 0.229 ± 4.39 0.0144 ± 0.31 0.79 ± 17.06 43.3 ± 0.94 11.18 ± 0.24 9.50 ± 0.21

t,;41 3.36±0.06 0.324 ± 6.18 0.0172 ± 0.36 0.85 ± 17.66 47.7 ± 0.99 11.24 ± 0.23 9.70 ± 0.20

t5;47 3.60 ± 0.07 0.264 ± 5.54 0.0180 ± 0.36 0.94 ± 18.79 46.6 ± 0.93 11.10 ± 0.22 9.10 ± 0.18

ts; 65 3.68 ± 0.07 0.239 ± 5.21 0.0112 ± 0.21 0.95 ± 17.86 48.6 ± 0.91 10.86 ± 0.20 9.50 ± 0.19

Table 3. (continuation)

M3 Mash

ti;0 5.83 ± 0.11 0.046 ± 0.94 0.0000 ± 0.00 0.00±0.00 25.5 ± 0.53 11.53 ± 0.24 10.60 ± 0.22

t2; 17 3.56 ± 0.08 0.185 ± 3.49 0.0131 ± 0.27 0.37 ± 7.47 28.9 ± 0.59 11.90 ± 0.24 11.10 ± 0.23

t3;23 3.26 ± 0.06 0.153 ± 3.23 0.0137 ± 0.35 0.49 ± 12.49 25.5 ± 0.66 11.63±0.30 10.90 ± 0.28

t,;41 3.33 ± 0.07 0.245 ± 4.33 0.0185 ± 0.36 0.52 ± 10.17 32.2 ± 0.63 11.88 ± 0.23 11.10 ± 0.22

t5;47 3.61 ± 0.07 0.202 ± 3.98 0.0117 ± 0.28 0.55 ± 13.44 28.9 ± 0.70 10.91 ± 0.27 10.20 ± 0.27

ts; 65 3.65 ± 0.06 0.180 ± 3.52 0.0110 ± 0.23 0.50 ± 10.27 33.3 ± 0.69 11.88 ± 0.25 10.90 ± 0.23

M4 mash

ti;0 5.97 ± 0.13 0.034 ± 0.82 0.0000 ± 0.00 0.00±0.00 27.8 ± 0.52 12.73 ± 0.24 11.50 ± 0.22

t2; 17 3.77 ± 0.08 0.134 ± 3.06 0.0093 ± 0.19 0.64 ± 13.46 24.4 ±0.51 11.37 ± 0.24 9.80 ± 0.20

t3;23 3.59 ± 0.09 0.166 ± 4.69 0.0104 ± 0.15 0.86 ± 18.45 26.6 ± 0.57 11.24 ± 0.24 10.30 ± 0.26

t,;41 3.57 ± 0.06 0.177 ± 3.38 0.0139 ± 0.27 0.98 ± 18.62 26.6 ±0.51 10.84 ± 0.21 10.70 ± 0.21

t5;47 3.51 ± 0.07 0.203 ± 5.23 0.0127 ± 0.23 1.00 ± 17.88 31.1 ± 0.56 11.03 ± 0.20 9.50 ± 0.17

t«; 65 3.50 ± 0.09 0.201 ± 3.91 0.0105 ± 0.21 1.08 ± 21.34 30.0 ± 0.59 10.84 ± 0.21 10.10 ± 0.20

M5 Mash

ti;0 5.89 ± 0.12 0.036 ± 0.75 0.0000 ± 0.00 0.00±0.00 700.4± 14.22 12.02 ± 0.24 8.50 ± 0.17

t2; 17 3.53 ± 0.06 0.178 ± 3.39 0.0077 ± 0.20 0.07 ± 1.72 743.7± 19.11 12.40 ± 0.32 7.60 ± 0.20

t3;23 3.45 ± 0.05 0.185 ± 3.74 0.0065 ± 0.13 0.16 ± 3.37 751.5± 15.56 12.41 ± 0.26 8.90 ± 0.18

t,;41 3.60 ± 0.08 0.187 ± 4.21 0.0057 ±0.11 0.12 ± 2.37 862.5± 16.47 12.48 ± 0.24 8.40 ± 0.16

t5;47 3.35 ± 0.05 0.181 ± 3.48 0.0051 ± 0.12 0.15 ± 3.57 866.9±21.07 12.66 ± 0.31 8.40 ± 0.20

ts; 65 3.57 ± 0.04 0.181 ± 3.51 0.0047 ± 0.09 0.11 ± 2.06 815.9± 15.42 12.63 ± 0.24 8.40 ± 0.16

M6 Mash

ti; 0 6.08 ± 0.15 0.038 ± 0.69 0.0000±0.00 0.00±0.00 1010± 18.08 12. 93 ± 0.23 9.00 ± 0.16

t2; 17 3.68 ± 0.07 0.220 ± 4.21 0.0104 ± 0.24 0.21 ± 4.83 863.6± 19.95 10.36 ± 0.24 6.40 ± 0.15

t3; 23 3.43 ± 0.08 0.220 ± 4.32 0.0090 ± 0.18 0.23 ±4.51 1051± 20.70 12.19 ± 0.25 8.60 ± 0.17

t,; 41 3.54 ± 0.06 0.209 ± 3.94 0.0082 ± 0.21 0.18 ± 4.70 1047± 26.91 13.83 ± 0.36 9.20 ±0.24

t5; 47 3.42 ± 0.08 0.184 ± 3.71 0.0072 ± 0.15 0.22 ± 4.64 1008±21.07 14.07 ± 0.29 9.20 ± 0.19

t«; 65 3.43 ± 0.09 0.193 ± 4.01 0.0069 ± 0.15 0.24 ± 5.03 938.0±19.42 13.86 ± 0.27 9.50 ± 0.20

Note: mean values of triplicate determinations (n=3) ± standard deviation and significant differences a=0.05

a - expressed as lactic acid (g lactic acid I 100 g of mash); b - expressed as acetic acid (g acetic acid 1100 g of mash). 1 cP = 0.001 Paxs = 1 mPaxs

This trend is not found for M5 mash for which the dynamic viscosity continues to increase up to 41h of fermentation, after that for both the dynamic viscosity decreases. This observation has been verified, too, in the case of mashes M2 and M4, couple like composition. The highest concentration of ethyl alcohol was obtained for Ml mash.

From figures Fig. 1 (b) and Fig. 2 (a, b) it may be said that for the mashes with initial higher dynamic viscosity the increase of ethylic alcohol production and the increase of total acidity causes a decrease of dynamic viscosity after 17 h of fermentation.

6,2 6,0 5,8 5,6 5,4 5,2 5,0 4,8 %4,6 4,4 4,2 4,0 3,8 3,6 3,4 3,2 3,0

- - M4 —» - M6

£•15

20 30 40 Time. (V)

50 60 7C

F y sV

Ë* - -

Ë* Ft

20 30 40 Time, (h)

Fig. 1. (a) Ev( Evolution of

1,3 1,2 1,1 1,0 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0,0

— — — — JÊL

Z _ -■

/ . . - * r /> —

JfA —

u - • -m

/ —

—c^ M2

- - M4

—» - M6

110 100

90 80 70 60 50 40 30 20

ition; (c)

20 30 40 Time, (h)

50 60 70

20 30 40 Time, (h)

50 60 70

Fig. 2. (a) Evolution of alcoholic concentration of mashes during fermentation; (b) Evolution of dynamic viscosity (for M5 and M6 value of dynamic viscosity from graphic must be multiplied by 10 to get real values) of mashes during fermentation

3.2. Sensorialevaluation

For a better interpretation of the results of sensory evaluation they were represented in three spider web graphics (Fig.3.). According to these results, is found that the M5 and M6 mashes obtained the best scores only attribute stability; of these two mashes the M6 mashes is the highest stability. This is explained by the greater percentage of fine grinding of millet from the composition ofM6 mash.

Millet comes with a higher intake of protein and carbohydrates, compared with Spelt wheat. So, to get good scores for other attributes in sensory evaluation, too, is necessary to avoid high percentage of millet finely ground, but also for wheat, as is the case of the M5 and M6 mashes.

In the case of the attribute taste, the M3 mash M3 has the best result and it is followed by Ml and M2 mashes, in descending order. It was found a direct proportionality between the attribute taste and amount of Pilsner malt barley from their composition. The positive influence is due to higher concentration of free amino nitrogen (FAN), reducing sugars and aroma compounds that barley malt mashes they provide. Evolution of the attribute flavour was similar and nearly of that of taste attribute, and has a similar explain with previous attribute.

The texture samples analyzed was considered favorable and grouped for the first four samples, but samples M5 and M6 are given a score between 2 and 3 points more than the low.

This is due to consistency / excessive viscosity of the samples; assessors preferring the fermented mashes with medium consistently, generally (the case of the Ml, M2 and M4 mashes). By the score assigned to the attribute appearance by assessors can see that sample Ml, with a greater quantity of malt, but with a small amount of oats, get the highest score. This finding is strengthened by the major physical-chemical values of Ml mash.

— -O- — Ml mash

taotP ^

(a) (b) (c)

Fig. 3. (a) Spider web diagram forMl and M2 mashes; (b) Spider web diagram for M3 and M4 mashes; (c) Spider web diagram for M5 and M6 mashes

Based on research results it can be said that the pH, total and volatile acidity of cereal-based fermented mashes correspond to data from the literature [2,4,10], while the alcohol concentration is higher and the total dry substance is less. The mashes with a larger quantity of oats, but with a moderate malt content leads to a greater amount of alcohol for a ratio ofl:12 between the amount of grist (10 parts) and water.

In the technological variants analyzed found that a total duration of 41 hours of the fermentation, of which 23 h at 30 °C and 18 h at 4 °C ensures high physical-chemical and sensory corresponding. After this time, began to significantly depress of the total and volatile acidity and for some fermented mashes to gradually reduce the alcohol concentration. In the conclusion, a longer duration of 65 h of storage of the fermented mashes is notjustified.

Acknowledgements

This work was cofinanced from the European Social Fund through Sectoral Operational Programme Human Resources Development 2007-2013, project number POSDRU/89/1.5/S/63258 "Postdoctoral school for zootechnical biodiversity and food biotehnology based on the eco-economy and the bio-economy required by eco-san-genesys".

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