Frozen Dough and Partially Baked Bread: An Update

Enhancing freeze-thaw tolerance in baker's yeast: strategies and perspectives

Frozen dough technology is important in modern bakery operations, facilitating the transportation of dough at low temperatures to downstream sales points. However, the freeze-thaw process imposes significant stress on baker's yeast, resulting in diminished viability and fermentation capacity. Understanding the mechanisms underlying freeze-thaw stress is essential for mitigating its adverse effects on yeast performance. This review delves into the intricate mechanisms underlying freeze-thaw stress, focusing specifically on Saccharomyces cerevisiae, the primary yeast used in baking, and presents a wide range of biotechnological approaches to enhance freeze-thaw resistance in S. cerevisiae. Strategies include manipulating intracellular metabolites, altering membrane composition, managing antioxidant defenses, mediating aquaporin expression, and employing adaptive evolutionary and breeding techniques. Addressing challenges and strategies associated with freeze-thaw stress, this review provides valuable insights for future research endeavors, aiming to enhance the freeze-thaw tolerance of baker's yeast and contribute to the advancement of bakery science.

Metabolomic insights into the effect of chickpea protein hydrolysate on the freeze-thaw tolerance of industrial yeasts

The use of frozen dough is an intensive food-processing practice that contributes to the development of chain operations in the bakery industry. However, the fermentation activity of yeasts in frozen dough can be severely damaged by freeze-thaw stress, thereby degrading the final bread quality. In this study, chickpea protein hydrolysate significantly improved the quality of steamed bread made from frozen dough while enhancing the yeast survival rate and maintaining yeast cell structural integrity under freeze-thaw stress. The mechanism underlying this protective role of chickpea protein hydrolysate was further investigated by untargeted metabolomics analysis, which suggested that chickpea protein hydrolysate altered the intracellular metabolites associated with central carbon metabolism, amino acid synthesis, and lipid metabolism to improve yeast cell freeze-thaw tolerance. Therefore, chickpea protein hydrolysate is a promising natural antifreeze component for yeast cryopreservation in the frozen dough industry.

Alleviative effects of mannosylerythritol lipid-A on the deterioration of internal structure and quality in frozen dough and corresponding steamed bread

The effects of mannosylerythritol lipid-A (MEL-A) on the quality of frozen dough and corresponding steamed bread were investigated. The results revealed that the rheological properties of frozen dough were improved with the increment of MEL-A (0%-2.0%). Adding 1.5% and 2% MEL-A significantly reduced the moisture migration and enhanced the water-holding capacity of the frozen dough. Microstructure observation demonstrated that high levels of MEL-A enabled more starch granules to be embedded in the dough network. A series of product quality assessments illustrated that frozen dough steamed bread containing 2.0% of MEL-A had the largest specific volume (2.981 mL/g), the highest springiness (77.47%), more uniform and porous crumb structure. Moreover, MEL-A exhibited a positive effect on steamed bread's flavor profile, which was explored for the first time in this study. Hence, these results suggested that MEL-A has promising applications as a novel dough improver in the food industry.

Characteristics and applications of plant-derived antifreeze proteins in frozen dough: A review

Frozen dough technology has been widely used in the food industry at home and abroad due to its advantages of extending shelf life, preventing aging, and facilitating refrigeration and transportation. However, during the transportation and storage process of frozen dough, the growth and recrystallization of ice crystals caused by temperature fluctuations can lead to a deterioration in the quality of the dough, resulting in poor sensory characteristics of the final product and decreased consumption, which limits the large-scale application of frozen dough. In response to this issue, antifreeze proteins (AFPs) could be used as a beneficial additive to frozen dough that can combine with ice crystals, modify the ice crystal morphology, reduce the freezing point of water, and inhibit the recrystallization of ice crystals. Because of its special structure and function, it can well alleviate the quality deterioration problem caused by ice crystal recrystallization during frozen storage of dough, especially the plant-derived AFPs, which have a prominent effect on inhibiting ice crystal recrystallization. In this review, we introduce the characteristics and mechanisms of action of plant-derived AFPs. Furthermore, the application of plant-derived AFPs in frozen dough are also discussed.

A combined use of different functional additives for improvement of wheat flour quality for bread making

BACKGROUND

Low-protein wheat flour can produce bread with poor texture and appearance, reducing its nutritional value and market appeal. This is a growing concern for both the food industry and consumers relying on wheat as a dietary staple. The present study evaluated the individual and combined effects of bacterial xylanase (BX), maltogenic α-amylase (MG), vital gluten (VG) and ascorbic acid (AA) with respect to improving weak flour properties for bread making.

RESULTS

BX, VG and AA improved gluten Index (GI), whereas MG was employed for optimizing amylolytic-activity in flour. VG increased the water absorption (WA) capacity of flour and prolonged dough development time (DDT). The dough stability (DST) was increased by BX and VG. BX and MG decreased crumb firmness (CF) and showed anti-staling effect. All additives reduced bake loss, increased loaf volume (LV) and retained or improved sensory attributes of bread. However, MG at 60 mg kg-1 (MG60), BX at 30 mg kg-1 (BX30), VG at 5% (VG5) and AA at 50 mg kg-1 (AA50) were found to be the most suitable for evaluating in combinations. Ternary combinations of MG60, BX30, VG5 or AA50 imparted significantly (P < 0.05) positive impacts on GI, WA, DDT, DST, CF, LV and sensory attributes compared to control, individual and binary combinations.

CONCLUSION

The PCA suggested that a combination of MG60 + VG5 was more similar to MG60 + BX30 + VG5, whereas, MG60 + BX30 and MG60 + AA50 were more related to MG60 + BX30 + AA50 combination, but all of these combinations showed the improvement in the characteristics compared to control flour. © 2023 Society of Chemical Industry.

Impact of Different Frozen Dough Technology on the Quality and Gluten Structure of Steamed Buns

To advance the industrialization production of steamed buns, the current study explored the freeze-stability of unfermented, pre-fermented and par-steamed frozen dough. The results showed that the steamed bun made from unfermented dough with 2.0% yeast, the pre-fermented dough with a pre-fermented time of 30 min and the par-steamed dough with a pre-steamed time of 15 min showed the best sensory properties quality upon frozen storage. The gassing power of un- and pre-fermented dough gradually decreased, and dough with longer pre-fermented time exhibited more evident loss of gassing power. Freeze-induced depolymerization of gluten protein was the least distinct in the par-steamed dough, followed by the pre- and un-fermented dough, which was probably related to the superior freeze stability of glutenin-gliadin macro-crosslinks upon the pre-steaming stage. The surface hydrophobicity of gluten proteins of frozen dough decreased during the initial storage and was enhanced subsequently, which was related with the combined effects of the unfolding and synchronous aggregation induced by freezing and steaming, respectively. Moreover, the surface hydrophobicity of gluten in par-steamed frozen dough and steamed buns was more resistant to frozen storage, which was probably attributed to the established stable structure during the pre-steaming process.

Effect of subfreezing storage on the qualities of dough and bread containing pea protein

BACKGROUND

In this paper, -6, -9 and -12 °C were selected as subfreezing temperatures of dough containing pea protein based on the results of low-field nuclear magnetic relaxation time. The effect of storage at subfreezing temperatures on dough properties was then investigated and compared with sample storage at -18 °C.

RESULTS

The pH value, springiness, resilience, cohesiveness of dough and sensory score of bread gradually decreased and the hardness and water loss rate of dough gradually increased with the extension of storage time. However, dough hardness, viscoelasticity and fermentation volume were maintained more effectively in subfreezing storage than in -18 °C storage. The subfreezing temperature could alleviate the damage of gluten network structure in frozen dough by ice crystals and was beneficial in maintaining the elasticity of gluten proteins. The network system of pea protein, gluten protein and starch granules in dough storage at -9 and -12 °C was more tightly connected and the microstructure was similar to that at -18 °C. There was no significant difference between the quality of bread made from the dough stored at subfreezing temperature and that stored at -18 °C for 1-6 weeks, and the preservation effect at -12 °C was closer to that at -18 °C.

CONCLUSION

Subfreezing storage can keep the stability of dough containing pea protein close to traditional frozen storage (-18 °C), which provides a new method for storage and transportation of frozen dough. © 2022 Society of Chemical Industry.

Development of Freeze-Thaw Stable Starch through Enzymatic Modification

The use of unmodified starch in frozen foods can cause extremely undesirable textural changes after the freeze-thaw process. In this study, using cyclodextrin glucanotransferase (CGTase) and branching enzymes, an amylopectin cluster with high freeze-thaw stability was produced, and was named CBAC. It was found to have a water solubility seven times higher, and a molecular weight 77 times lower, than corn starch. According to the results of a differential scanning calorimetry (DSC) analysis, dough containing 5% CBAC lost 19% less water than a control dough after three freeze-thaw cycles. During storage for 7 days at 4 °C, bread produced using CBAC-treated dough exhibited a 14% smaller retrogradation peak and 37% less hardness than a control dough, suggesting that CBAC could be a potential candidate for clean label starch, providing high-level food stability under repeated freeze-thaw conditions.

Effect of hydrocolloids on physical, thermal and microstructure properties of par-baked baguette during frozen storage

The retrogradation of starch occurs in the process of freezing storage of par-baked baguette, resulting in easy staling and a decrease of consumer acceptance. The objective of this study was to assess whether the staling of par-baked baguette could be improved by the addition of Arabic gum (AG), Sodium alginate (SA), and Sesbania gum (SG). The physical, thermal dynamic, and microstructure properties of par-baked baguette during frozen storage were analyzed. The addition of hydrocolloid increased the moisture of the baguette and delayed the water migration, which was beneficial to improve the dough formation and gas capacity, hinder the growth of ice crystals, and reduce the hardness of the baguette. These properties were more pronounced with increasing freezing storage periods. These hydrocolloids could slow down the rate of recrystallization, which reduced the enthalpy change and crystallinity of par-baked baguette. It was also found that the hydrocolloids incorporated baguette was smooth in the crumb microstructure. In general, these results suggested that the incorporation of hydrocolloids improved the quality and anti-staling mechanism of the par-baked baguette during frozen storage which can be used as potential improvers to increase freezing stability in the formulation of the baguette.

Dough rheology, antioxidants, textural, physicochemical characteristics, and sensory quality of pizza base enriched with onion (Allium cepa L.) skin powder

In the present research, wheat flour was replaced with onion skin powder (OSP) in 2%, 3.5%, and 5% concentration along with control to produce different pizza base variants. Prepared pizza doughs and base were investigated for different quality parameters. Rheology revealed that increased concentration of OSP elevated the storage modulus (G') (solid nature) of pizza doughs. Colour measurement of both the doughs and pizza base exhibited lightness in control (L* 86.46 ± 0.39) and darkness in 5% OSP variant (L* 46.43 ± 0.69). Physicochemical investigation showed no significant difference however, a gradual increase was obtained in fiber, water, and oil holding capacity of pizza base. Texture properties showed that the addition of OSP imparted an increased trend of hardness i.e. 5% OSP variant had maximum hardness (14.87 ± 0.20 N). A higher level of total phenols, total flavonoids, and antioxidant activity was obtained in fortified products, which exhibits onion skin as a natural source of antioxidants for functional foods. Sensory evaluation revealed OSP 2% as the most accepted variant in terms of overall acceptability. The storage study of the pizza base revealed that controlled environment was the best-suited atmosphere for a longer shelf-life of pizza base.

A Methodology to Assess the Suitability of Food Processing Technologies for Distributed Localised Manufacturing

Food processing technology research and development activities have historically been driven by large-scale manufacture upscaling drivers to profit from economies of scale. Increasing demand for high-quality food with pioneering texture profiles, consumer needs for personalised products impacting product formulation (i.e., fat, sugar and micronutrient content), and constrained availability of ingredients and resources are pressuring industrialists to utilise alternative technologies to enable a more sustainable food supply. Distributed and localised food manufacturing (DLM) has been identified as a promising strategy towards future sustainable systems with technology representing one of its cornerstones. Innovative methods and tools to support the selection of the best alternative technologies for DLM are required. This paper provides an overview of food processing technologies and includes a novel classification created to support future assessments. A novel qualitative assessment method encompassing multiple criteria to understand specific food technologies suitability for future DLM systems is presented. Finally, research benefits are explored through the application of the assessment method to several selected technologies with promising potential in future food manufacturing. The results demonstrate that this methodological approach can assist in the adoption of DLM food systems through the selection of the best technologies integrating individual manufacturer requirements.

Porous Crumb Structure of Leavened Baked Products

Quality evaluation of the porous crumb structure of leavened baked goods, especially bread, has become a vast study area of which various research studies have been carried out up to date. Here is a brief review focusing on those studies with six main parts including porous crumb structure development, crumb cellular structure analysis, application of fractal dimension for evaluating crumb cellular structure, mechanical and sensorial properties of crumb structure, changes of porous crumb structure with staling, and modifications to obtain a well-developed porous crumb structure and retard staling. Development of the porous crumb structure mainly depends on dough ingredients and processing conditions. Hence, certain modifications for those factors (incorporating food hydrocolloids, emulsifiers, improvers, etc.) have been conducted by cereal sciences for obtaining well-developed porous crumb structure and retard staling. Several image analysis methods are available for analyzing microstructural features of porous crumb structure, which can directly affect the mechanical and sensorial properties of the final product. A product with a well-developed porous crumb structure may contain the property of higher gas retention capacity which results in a product with increased volume and reduced crumb hardness with appealing sensorial properties.

Evaluation of different hydrocolloids to improve dough rheological properties and bread quality of potato-wheat flour

The aim of study was to investigate the effect of hydroxylpropylmethylcellulose (HPMC), arabic gum (AG), konjac glucomannan (KG) and apple pectin (AP) at 2% (w/w, potato-wheat flour basis) on the potato-wheat dough (the mass ratio was 1:1) rheological, fermentation and bread making properties. The tan δ of potato-wheat dough was significantly increased upon addition of adding HPMC which was close to wheat dough (0.531). Moreover, dough height during fermentation process was significantly improved on addition of hydrocolloids, with the order of HPMC (23.1 mm) > AP (19.3 mm) > AG (18.6 mm) > KG (13.6 mm). Protein bands of potato-wheat dough were pale in the presence of hydrocolloids, suggesting the formation of higher molecular weight aggregates formed between proteins-hydrocolloids or proteins-proteins after fermentation process. Furthermore, HPMC significantly increased specific volume (from 1.45 to 2.22 ml/g), and hydrocolloids restricted the retrogradation of starch in potato-wheat breads.

The effect of Arabic gum on frozen dough properties and the sensory assessments of the bread produced

The use of hydrocolloids in frozen dough has become frequent as bread improvers due to their anti-staling effect. Nevertheless, the impact of both different frozen storage and Arabic gum level in non-prefermented flat dough with following thawing procedure have not been studied. This work intended to study the effect of three different ratio of Arabic gum on rheological properties of 1, 7, and 30 days of frozen storage and the quality of the bread made from. In order to gain the least detrimental effects on gluten network, we used rapid rate freezing and microwave heating in thawing stage. Rheological results showed that the unfrozen samples to which Arabic gum had been added rendered the highest resistance to extension. The resistance of gum fortified samples were less than fresh dough, however the decline was not significant in 3.0% Arabic gum dough kept in a month storage (p > .05). The similar findings were obtained for extensibility and adhesiveness; in which the maximum incorporation of Arabic gum lessen the destructive impact of long freezing storage. Addition of 3% gum could be able to retard staling through an increment in hydrophilic bonds between water molecules and amylose during thawing (p < .05). The overall rating of Arabic gum enriched samples was similar with bread made from non-frozen dough, even after 30 days of storage as indicated by the sensory evaluation of breads.

PRACTICAL APPLICATIONS

Producing a chapatti-like fermented bread without long fermentation period. Formulation a frozen dough without using chemical additives. Introducing a proper use of a new defrosting method with the aim of achieving a better texture. Improvement in retarding staling by the use of Gum Arabic after 7 days.

Rheological properties and bread quality of frozen sweet dough with added xanthan and different freezing rate

In this paper the effects of frozen storage time, xanthan gum and rate of freezing on frozen sweet dough properties and unfermented bread quality was investigated. Results revealed that the water holding capacity, WHC, K₁ (stress decay rate) and K₂ (residual stress at the end of the stress relaxation experiment) values of frozen dough decreased with increasing frozen storage time and decreasing freezing rate; while the lowest values for these parameters were obtained for samples without xanthan gum. The amount of unfreezable water increased and freezable water decreased with addition of xanthan gum. Glass transition temperature for fresh or frozen sweet were around -37 and -39 °C, respectively. Addition of xanthan gum increased the glass transition temperature of fresh and fozen sweet dough. Firmness and gumminess of sweet bread increased during frozen storage which led to lower specific volume of frozen sweet bread. Increasing freezing rate and addition of xanthan gum to dough formulation improved the texture and specific volume of the final bread.

Effect of freezing rate on rheological, thermal and structural properties of frozen wheat starch

Native wheat starch was frozen at different rates (0.18, 0.37 and 1.54 °C min⁻¹) and then evaluated for dough making.

Bread Staling: Updating the View

Staling of bread is cause of significant product waste in the world. We reviewed the literature of the last 10 y with the aim to give an up-to-date overview on processing/storage parameters, antistaling ingredients, sourdough technology, and measurement methods of the staling phenomenon. Many researchers have been focusing their interest on the selection of ingredients able to retard staling, mainly hydrocolloids, waxy wheat flours (WWF), and enzymes, but different efforts have been made to understand the molecular basis of bread staling with the help of various measurement methods. Results obtained confirm the central role of amylopectin retrogradation and water redistribution within the different polymers in determining bread staling, but highlighted also the importance of other flour constituents, such as proteins and nonstarch polysaccharides. Data obtained with thermal, spectroscopy, nuclear magnetic resonance, X-ray crystallography, and colorimetry analysis have pointed out the need to encourage the use of one or more of these techniques in order to better understand the mechanisms of staling. Results so far obtained have provided new insight on bread staling, but the phenomenon has not been fully elucidated so far.

Perspective of surface active agents in baking industry: an overview

Different researchers have previously used surfactants for improving bread qualities and revealed that these compounds result in improving the quality of dough and bread by influencing dough strength, tolerance, uniform crumb cell size, and improve slicing characteristics and gas retention. The objective of this review is to highlight the areas where surfactants are most widely used particularly in the bread industries, their role and mechanism of interaction and their contribution to the quality characteristics of the dough and bread. This review reveals some aspects of surface-active agents regarding its role physiochemical properties of dough that in turn affect the bread characteristics by improving its sensory quality and storage stability.