A

A.P. Dorosh, O.I. Skovorinskaya

Scientific adviser: PhD in Technical Sciences N.N. Gregirchak

National University of Food Technologies

Effect of improvers on the microbiological indexes of products of wheat flour

A stable supply of the population with quality bakery products, which have high nutritional value and functional properties is a paramount objective of the baking industry. With a variable quality of wheat flour, the use of such food additives as bread improvers gives the ability to consistently produce high quality products.

The purpose of this work is to examine the effect of improvers of various composition on the microflora of bread.

We used as prototypes the improvers of the following composition: “Freshness” (beer protein − 0,2%), “Freshness K+” (bean powder - 1.4%), “Freshness” (potato powder - 2%). The objects of analysis were also the finished bread samples made with and without improvers (control), in accordance with the following formulation per 100 kg of flour: wheat bread (“Freshness K +” - 2,0 kg), wheat loaf (“Freshness +” - 2,0 kg), wheat branny crisp bread (“Freshness”- 2,0 kg”).

We defined such microbiological parameters as the number of mesophilic aerobic and facultative anaerobic microorganisms (NMAFAM), the presence of coliform group bacteria (CGB), molds and yeasts, the presence of bacteria of the genus Leuconostoc, the number of spore-forming (SFB) and lactic acid bacteria (LAB).

The initial stage of research was the microbiological analysis of the feedstock. The results are shown in Table 1.

Table 1

Microbiological indexes of feedstock

Microbiological indexes, CFU/g	Wheat flour	Beer protein	Bean powde	Potato powder
Microbiological indexes, CFU/g	result CFU/g
NMAFAM	5,7 х 10⁵	1,7 х 10⁶	1,1 х 10⁶	1,0 х 10⁶
LAB	<10³	<10³	<10³	<10³
Yeasts	<100	<100	<100	<100
Molds	1,0 х 10²	1,0 х 10²	1,0 х 10²	1,0 х 10²
SFB	0,9 х 10²	0,8 х 10²	0,9 х 10²	0,7х 10²
CGB	n/f	n/f	n/f	n/f
Putrefactive bacteria	<10³	<10³	<10³	<10³
Bacteria of the genus Leuconostoc	3 х 10³	<10³	<10³	<10³

* n/f - not found.

In samples of raw materials for improvers (beer protein, bean and potato powders NMAFAM index was increased by 2 orders in comparison with the standard (5,0 × 10⁴) indicated in TC 15.3 – 05417118.024 - 2002 vegetable powders. Analysis of wheat flour showed the NMAFAM value 5 7 x 10⁵ CFU is also higher than normal. All other parameters, including the number of spore-forming bacteria and mold matched standards.

Bacteria of the genus Leuconostoc (3 × 10³ CFU/g) were detected in a sample of wheat flour, the presence of which is not specified, but may cause slimming crumb, thereby reduces the quality of bread.

The final step was to check the microbiological parameters of the finished bakery products. The verification was carried out immediately after baking, and on day 4 of storage, the results are shown in table 2 and table 3 respectively.

All test samples immediately after baking had NMAFAM index a bit higher than NMAFAM index compared with the value of the standard (1,0 × 10³).

Table 2

Microbiological indexes of different bread recipes immediately

after baking

Microbiological indexes, CFU/g	wheat loaf (cont.)	wheat loaf with “Freshn-ess”	wheat branny crisp bread (cont.)	wheat branny crisp bread with “Freshn-ess”	Wheat bread (cont.)	Wheat bread with “Fres-hness K +”
Microbiological indexes, CFU/g	result CFU/g
NMAFAM	1,0 × 10³	2,0 × 10³	2,0 × 10³	1,0×10³	2,0× 10³	3,0 × 10⁷
LAB	<10³	<10³	<10³	<10³	<10³	<10³
Yeasts	<100	<100	<100	<100	<100	<100
Molds	<100	<100	<100	<100	<100	<100
SFB	2,3 х 10²	<100	1,8 х 10²	8,4 х 10²	9,4 х 10²	7,8 х 10²
CGB	n/f	n/f	n/f	n/f	n/f	n/f
Putrefactive bacteria	<10³	<10³	<10³	<10³	<10³	<10³
Bacteria of the genus Leuconostoc	<10³	<10³	<10³	<10³	<10³	<10³

Table 3

Microbiological indexes of different bread recipes

on the 4th day of storage

Microbiological indexes, CFU/g	wheat loaf (cont.)	wheat loaf with “Freshness”	wheat branny crisp bread (cont.)	wheat branny crisp bread with “Freshness	Wheat bread (cont.)	Wheat bread with “Freshness K +”
Microbiological indexes, CFU/g	Результат КОЕ/г
NMAFAM	3,4 × 10³	1,0 × 10³	6,9 × 10³	2,4×10³	4,6 × 10³	3,7× 10³
LAB	<10³	<10³	<10³	<10³	<10³	<10³
Yeasts	<100	<100	<100	<100	<100	<100
Molds	<100	<100	1,0 х 10²	1,0 х 10²	<100	<100
SFB	3,0 х 10²	1,2 х 10²	1,9 х 10²	9,3 х 10²	1 х 10³	8,3 х 10²
CGB	н/о	н/о	н/о	н/о	н/о	н/о
Putrefactive bacteria	<10³	<10³	<10³	<10³	<10³	<10³
Bacteria of the genus Leuconostoc	<10³	<10³	<10³	<10³	<10³	<10³

On the 4th day NMAFAM increased by 5 times for the control, and by 2.4 times at the average for bread with improver. Fungi were found on the 4th day in all samples, including controls that do not comply with the standard that specifies the inadmissibility of them in the finished product. The spore-forming bacteria were found in bakery products. Bacteria of the genus Leuconostoc were not detected.

The quality of bakery products depends on the baking properties of flour, yeast, other raw materials, state and change of their carbohydrate-amylase, protein and lipid-lipase complexes during the technological process, as well as microorganisms. According to this the results received indicate only that the improvers can not influence on the microflora of finished bakery products.