Improvement of Bread Quality by Adding Wheat Germ Fermented with Lactobacillus plantarum dy-1

Yansheng Zhao,Dong Ying,Jiayan Zhang,Lianzhong Ai,Xiang Xiao,Yixing Wei

doi:10.1155/2020/9348951

Abstract

Fermentation has been considered as an effective way to improve the nutritional and sensory quality of food materials. In this paper, fermented wheat germ (FWG) was prepared by fermentation with Lactobacillus plantarum dy-1 and added as an ingredient in bread making for nutrition and quality improvement. The amounts ranged from 1 % to 6 % of FWG were added into ingredients for bread making, the similar amounts of raw wheat germ (RWG) were used as control, and the wheat flour without germ addition was used as blank. Then, bread quality was evaluated through nutrition, texture, and flavor analyses. The results showed that 4% of FWG addition had the ability to increase the specific volume, slow down the aging process, and improve the color and luster of bread. A significant increase in free amino acid content was observed in the FWG bread, which could be helpful to enrich the flavor substances in bread. The flavor analysis of bread showed that more volatile compounds mainly alcohols and aldehydes were present in FWG bread compared with RWG bread. In the fermentation process, the pH value was decreased and the total titratable acidity (TTA) was enhanced to inhibit the growth of microorganisms. Therefore, the addition of FWG could not only enhance its nutritional properties, but also improve the flavor, quality, and structural features of bread. Moreover, it exhibited a good availability to extend the shelf life of bread.

Highlights

Wheat is one of the most significant staple food sources all over the world
We found that the content of free amino acids in fermented wheat germ (FWG) increased much more than that of raw wheat germ (RWG) without fermentation, and significant increase of phytase and decrease of phytic acid were observed [12]. e lipase and lipoxygenase activities were markedly lower by 55.3% and 76.3%, respectively
Studies revealed that there were no significant difference in terms of specific volume between the wheat bread and the bread adding maximum 4% of FWG (Table 1), whereas further increase of FWG will cause a decrease in specific volume, especially more than 5%

Summary

Introduction

Wheat is one of the most significant staple food sources all over the world. Normally, the wheat kernel can be roughly divided into three parts: the endosperm, germ, and multiple histological outer layers [1], in which wheat germ is the most nutritious part being rich in protein (26%), sugar (17%), fat (11%), and minerals (4%) [2] and it contains a high amount of vitamins and functional components, including alpha and beta-tocopherols, vitamin E, vitamin B, dietary fiber, and phytochemicals such as flavonoids and phytosterols [3].the application of wheat germ is very limited in staple food. E presence of wheat germ in bread products leads to technological disadvantages and inferior quality compared to bread with refined flour, such as the decrease in bread loaf volume, textural changes, and visual modifications [6]. The textural properties of food products could be decreased by adding wheat germ because of the high content of dietary fiber in it. In this case, some methods can be applied to improve the sensory characteristics of bread made of wheat flour with germ addition, such as thermal and nonthermal treatments or addition of inhibitors to inactivate enzymes [7].

Methods

Results

Conclusion