Gorkem Ozulku

The aim of this study is to provide an alternative bakery practice by evaluating the effects of cold fermentation (backslopping at 7 and 15 °C) and cold storage (stored at 7 and 15 °C) after backslopping on Type I sourdough characteristics and the technological performance of the corresponding breads. Sourdough characteristics (pH, acidity, and microbial counts), bread quality (texture and color), storage behavior, and volatile compound profiles (VoC) were investigated to compare the extent to which these treatments improve product quality. No significant difference was observed in pH and total titratable acidity among the sourdoughs. However, the fermentation quotient of the cold storage group was higher than that of the cold fermented group. Backslopping at cold fermentation temperatures (7 and 15 °C) caused a significant reduction in lactic acid bacteria counts. Conversely, cold fermentation and cold storage at 15 °C led to a significant increase in yeast counts. From a technological perspective, bread produced with sourdough backslopped at 15 °C exhibited a higher specific volume than breads produced with the other cold-treated sourdoughs. At the end of the storage period, the bread made with cold-backslopped sourdough at 7 °C had the highest hardness value, while others remained similar. Principal component analysis (PCA) of volatile compounds revealed that cold-stored sourdoughs were clustered apart from room-temperature-stored sourdoughs, mainly driven by ethyl hexanoate and hexyl acetate. Heptanoic acid was among the key VOCs contributing to the positioning of breads made with cold-stored sourdoughs in the PCA. In conclusion, these findings demonstrate that backslopping and storage at 15 °C offer an industrially relevant production strategy while improving textural properties and VoC profiles.

This study evaluated the effects of the partial baking (par-baking) method on bread quality, staling properties, volatile compound profile, and estimated glycemic index (eGI) of some traditional Turkish bread types, and compared the results with those of regular bread (RB). Bread samples resembling Afyonkarahisar potato bread and Vakfıkebir bread were produced under laboratory conditions and named Afyonkarahisar potato style bread (APSB) and Vakfıkebir style bread (VKSB). APSB and VKSB were subjected to par-baking (7 min at 220 °C for APSB and 9 min at 220 °C for VKSB), followed by frozen storage at −18 °C for up to 60 days and final baking. Also, quality changes in the breads after final baking were assessed over 5 days (days 0, 1, 3, and 5) and compared with conventionally baked control samples. The reduction in specific volume due to par-baking was more pronounced in regular bread than in the traditional bread samples. Hardness values of par-baked breads increased significantly after 60 days of frozen storage for all bread types (p < 0.05). Storage of breads after final baking caused substantial changes in textural properties, but no significant differences were observed in terms of staling rate among the non-par-baked samples during 5 days of storage at room temperature (p = 0.078). VKSB consistently exhibited the lowest eGI values for both the non-par-baked group and the par-baked group. Principal component analysis (PCA) clearly separated the volatile compound profiles of non-par-baked breads (VKSB-Day 0 and APSB-Day 0) from those of regular bread and par-baked breads. The findings of this study suggest that par-baking technology is a promising approach for breads similar to traditional breads, enabling wider consumption without marked quality deterioration up to 30 days and resulting in a lower estimated glycemic index (eGI) than regular bread.

This study investigates the effects of microbial bioprocessing (MB), ultrasound treatment (UT), and their combined application (hybrid method, HM) on the functional and nutritional enhancement of wheat bran (WB) and its impact on bread quality. MB was performed by using Saccharomyces cerevisiae with Levilactobacillus brevis LABE 32 (MB32) and Lactiplantibacillus plantarum LABE 29 (MB29). MB32 significantly increased soluble dietary fiber (SDF) and reduced phytic acid content by up to 25.7% when compared to the control. UT further decreased phytic acid content by 52.2% and enhanced phenolic compound release, contributing to improved antioxidant activity. The hybrid method (HM) demonstrated the strongest effect, reducing phytic acid content by 95% and enhancing antioxidant properties, including a 2.4-fold increase in bound antioxidant activity (bound-AA). Bread produced from modified WB showed improvements in specific volume (SV), texture, and nutritional composition. The HM-treated WB yielded bread with the highest SV, approximately 10% greater than the control, while MB29 produced significantly harder bread than other samples (p < 0.05). The HM-treated bread had the highest crust L* value and softest texture (p < 0.05). Nutritionally, only UT and HM treatments significantly increased the total dietary fiber (TDF) content, with the most pronounced increase observed in the HM treatment. Phytic acid degradation in the WB modified with MB32 and UT was in accordance with their breads, notably lowering phytic acid content. Additionally, MB32 and HM increased total phenolic content (TPC) and antioxidant activity, enhancing the bread’s overall nutritional quality. In conclusion, the hybrid application of MB and UT (HM) proved to be the most effective in improving the functional and nutritional properties of WB and the resulting bread, including increased dietary fiber content, reduced phytic acid levels, and enhanced antioxidant activity.

The interest in gluten-free (GF) products has been growing since both the increase in prevalence of celiac disease and the preferences of GF diet. In this study, the contribution of psyllium powder (PP) to gluten-free (GF) bread quality, dough rheology and volatile compounds (VCs) profile was investigated throughout the frozen storage period of GF dough (-30 °C for 0, 7, 15, and 30 days). GF doughs containing 7.5% PP (PSY1) and 15% PP (PSY2) had lower tanδ value than GF control dough (p<0.05) according to the results obtained from fundamental rheological analysis. Frozen storage caused no effect on the tanδ value of PSY1 and PSY2 (p ≥ 0.05). PP addition increased the specific volume (SV) of GF breads (p<0.05). No significant effect of frozen storage on SV was shown for PSY2 while SV values of GF control bread (GFB) and PSY1 decreased (p<0.05). Lower crumb hardness was shown for PSY1 and PSY2 on day 0. Significant effect of frozen storage on crumb hardness was observed for PSY1 on day 30 while harder crumb structure was shown for GFB throughout the frozen storage (p<0.05). Psyllium addition led to a significant reduction in both L* value of crust and crumb color (p<0.05). In the VCs analysis performed by HS/GC-MS, ethanol and 1-butanol, 3-methyl from alcohol group, butanal, 3-methyl- and hexanal from aldehydes were common for GFB and GF breads containing psyllium. 1-butanol, 3-methyl-, butanal, 3-methyl- and hexanal were the VCs of PSY1 and they were also shown after frozen storage. This study suggested that quality deterioration due to frozen storage was less in gluten-free breads containing psyllium.

There is a need to increase the consumption of whole wheat bread (WWB) due to its health benefits by overcoming its poor technological quality and improving its sensory characteristics. In this study, sourdough bread-making and frozen dough technology were combined to provide fresh WWB at any time with better quality. Also, it was aimed to investigate the effects of three types of sourdough (type I, II, and IV) on the final quality of WWB during frozen storage (−30 °C, 14 and 28 days). The tan δ of WWB with type I sourdough was highest at the end of the frozen storage. Freezable water content was lower on day 0 for WWB with type II and IV sourdough than other bread types. No significant effect of frozen storage was observed in bread types in terms of an α helix structure, except for WWB with type I sourdough. A lower hardness increment was shown in WWB with baker’s yeast and WWB with type II sourdough over 14 days of frozen storage when compared to other bread types. WWB with type I sourdough and WWB with type IV sourdough were differentiated from other bread samples in volatile compound (VC) analysis on frozen storage days 28 and 0, respectively. The frozen storage of WWB with baker’s yeast and WWB with type II sourdough caused no notable changes in the VCs profile. These results suggest that a less detrimental effect of frozen storage was observed in WWB with type II sourdough, indicating a more favorable choice for producing WWB with sourdough.

Fish skin gelatin, as a waste product of sea bream, was used to obtain fish gelatin hydrolysate (FGH) with the treatment of alcalase (alc) and savinase (sav). The functional properties of FGHs and their usage possibilities in frozen dough bread making were investigated. FGH treated with alc showed a higher emulsifying stability index (189 min), while FGH treated with sav showed greater foaming capacity (27.8%) and fat-binding capacity (1.84 mL/g). Bread doughs were produced using two FGHs (alc and sav) and their combination (FGH-alc + FGH-sav). Using FGH treated with these enzymes individually was more effective than their combination in terms of polyacrylamide gel electrophoresis (SDS-PAGE) results and bread quality (specific volume and hardness). The addition of FGH into bread dough showed no significant effect on bread dough viscoelasticity (tan δ), while the increment level of tan δ value for control dough was higher than the dough containing FGH after frozen storage (−30 °C for 30 days). The highest freezable water content (FW%) was found in control dough (33.9%) (p < 0.05). The highest specific volume was obtained for control fresh bread and bread with FGH-alc, while the lowest volume was obtained for fresh bread containing FGH-sav (p < 0.05). After frozen storage of the doughs, the bread with FGH-alc showed the highest specific volume. FGH addition caused a significant reduction in the L* (lightness) value of fresh bread samples when compared to control bread (p < 0.05). This study suggested that usage of FGH-alc in bread making decreased the deterioration effect of frozen storage in terms of the specific volume and hardness of bread.

The effect of casein savinase hydrolysate (CSH) usage on frozen dough (1%, 1.5% and 2%, g/100 g flour) was investigated in terms of rheological, thermal and structural characteristics of wheat doughs and the textural and color properties of corresponding breads. Rheological measurements showed that CSH addition into dough led to a reduction in G′ and G″ values, but a similar trend was not observed in frozen dough samples. The increase in protein band intensity was observed for control dough (CD) after frozen storage (−30 °C, 28 days), while there were no increases in the band intensities of the doughs with CSH. The freezable water content of unfrozen doughs decreased gradually with the addition of CSH, dependent on concentration level. Frozen storage caused a notable reduction in the α-helices structure of the CD sample (p < 0.05) while no significant variation was observed for the doughs containing CSH (p > 0.05). The lowest specific volume reduction and hardness increment were observed for the breads containing 1.5% and 2% CSH. Frozen storage caused a significant reduction in the b* value of bread crust (p < 0.05), while no significant effect was observed for L* and a* value during frozen storage (p > 0.05). Overall, CSH incorporation into frozen dough can be an alternative that could reduce the quality deterioration of frozen bread.

The effect of casein savinase hydrolysate (CSH) usage on frozen dough (1%, 1.5% and 2%, g/100 g flour) was investigated in terms of rheological, thermal, structural characteristics of wheat doughs and the textural and color properties of corresponding breads. Rheological measurement showed that CSH addition into dough led to a reduction of Gʹ and Gʹʹ values, but a similar trend wasn’t observed in frozen dough samples. The increase of protein band intensity was observed for control dough (CD) after frozen storage (-30 °C, 28 days) while there was no increases in band intensities of the doughs with CSH. The freezable water content of unfrozen doughs was decreased gradually with addition of CSH depended on concentration level. Frozen storage caused a notable reduction in α-helices structure of CD sample (p0.05). Lowest specific volume reduction and hardness increment were observed for the breads containing 1.5% and 2% CSH. Frozen storage caused a significant reduction on b* value of bread crust (p 0.05). Overall, CSH incorporation into frozen dough can be an alternative that could reduce the quality deteriorations of frozen bread.