Bread crumb quality assessment: a plural physical approach

Development and Evaluation of Calcium-Fortified Multi-Millet Biscuits: A Nutritious Alternative to Refined Wheat Flour

Millet products have garnered global recognition for their exceptional nutritional profile, appealing to various age demographics, and, therefore, fortifying such products with minerals can ensure nutritional security. This research explores the feasibility of utilizing millet as a substitute for refined wheat flour in biscuit production. Three distinct millet varieties were investigated: finger, pearl, and buckwheat. Employing response surface methodology (RSM), the optimal ratio of these flours was determined, resulting in a blend of 1.5:1:1, respectively. The optimized multi-millet biscuits were further enhanced with calcium fortification and subjected to comprehensive physico-chemical analysis. Proximate composition analysis revealed favorable levels of protein (5.472 ± 0.31%), ash (2.80 ± 0.57 g/100 g), and energy density (5.8015 ± 0.004 kcal/g), indicating a significantly higher protein content, enriched mineral profile, and high energy density as compared to refined wheat flour products. Sensory evaluation encompassing attributes such as color and texture and organoleptic assessment using a nine-point hedonic scale demonstrated favorable acceptance. Additionally, the overall acceptability of the biscuits remained consistently high throughout storage, ranging from 8.263 ± 0.65 (day 0) to 8.053 ± 0.85 (day 14). This study underscores the potential of multi-millet biscuits as a nutritious and palatable alternative to traditional wheat-based snacks, offering an avenue for diversifying dietary options and promoting healthier food choices.

Sorghum (Sorghum bicolor L. Moench) Gluten-Free Bread: The Effect of Milling Conditions on the Technological Properties and In Vitro Bioaccessibility of Polyphenols and Minerals

The absence of gluten proteins in sorghum allows for the production of baked goods that are suitable for celiacs. Previous studies have shown that the milling process affects the performance of sorghum flour in baked products, especially those that are gluten-free (GF). This study aimed to explore the effects of mill type (impact and roller) on flour properties and GF bread quality by assessing the technological quality, antioxidant activity, and mineral content of the bread. All particle populations of flour obtained via both millings presented a bimodal distribution, and the volume mean diameter (D 4,3) ranged from 431.6 µm to 561.6 µm. The partially refined milled flour obtained via polishing and impact milling produced bread with a soft crumb, fewer but larger alveoli in the crumb, and a structure that did not collapse during baking, showing the best performance in bread quality. In the in vitro bread digestibility assay, the total polyphenol content and antioxidant activity decreased during the digestion steps. High mineral (Cu, Fe, Mn, and Zn) contents were also found in a portion of the bread (120 g) made with whole sorghum flour; however, their potential bioavailability was reduced in the presence of a higher amount of bran.

Comparative safety analysis of newly prepackaged backed food products and those approaching the expiry date in Bangladesh

PURPOSE

The enrichment of microbial growth in prepackaged, frozen food goods from the day of manufacturing to the day of expiration has been the subject of recurrent concerns. These fortified foods are widely consumed by individuals of all ages in poor nations due to their ability to satisfy even the smallest of appetites. People often disregard the expiration dates printed on food packaging despite the fact that manufacturers are required by law to do so. This research looked into whether or not it was safe to consume packaged foods that were getting close to their expiration date. Finding out if people are exposed to hazardous microorganisms and how much bacteria is created daily on them.

MATERIALS AND METHODS

We collected six prepackaged backed food products samples of three types separately, where three were collected around manufacturing days and three were nearly expired days from different companies. We have assayed and identified the foodborne microbial communities among the samples by morphological study and different types of biochemical tests. After that, we tested how well various popular antibiotics worked against those isolates.

RESULTS

It showed that there are more bacterial communities that grow gradually day by day on prepackaged backed food products and nearly expired products that contain a large number of food-borne disease-causing bacteria that show mostly resistance against commonly used antibiotics.

CONCLUSION

Although nowadays the demand for prepackaged backed food products is increasing as ready-to-eat processed foods, mostly in developing countries, there's a serious health risk if we take the products that were produced a long time ago.

Comparison of wet and dried chickpea yeast in breadmaking

BACKGROUND

Chickpea yeast (CY), initiated by spontaneous fermentation of coarsely-ground chickpea in water, is considered a variant of conventional sourdough and contributes somewhat similarly to bakery products. As the preparation of wet CY prior to each baking process poses certain difficulties, its usage in dry form has been gaining interest. In this study, CY was used either directly in freshly prepared wet form or in freeze-dried and spray-dried forms at 50, 100 and 150 g kg^-1 levels (all on 14% moisture basis) in substitution with wheat flour to compare their effects on bread properties.

RESULTS

Utilization of all forms of CY did not noticeably change the contents of protein, fat, ash, total carbohydrate and damaged starch in the wheat flour-CY mixtures. However, falling numbers and sedimentation volumes of CY-containing mixtures decreased significantly, due probably to the increase in the amylolytic and proteolytic activities during chickpea fermentation. These changes somewhat corresponded to improved dough processability. Both wet and dried CY samples reduced pH levels of doughs and breads, and increased probiotic lactic acid bacteria (LAB) count. Total phenolic contents, antioxidant capacities and flavor scores of CY-containing breads were significantly enhanced. However, CY usage slightly influenced yield, moisture content, volume, color and hardness values of breads.

CONCLUSION

Effects of wet and dried forms of CY on bread properties were quite comparable, indicating that CY can be used upon properly drying similarly to the conventional wet form. © 2023 Society of Chemical Industry.

Effects of different types of electrolyzed waters on rheological characteristics of dough and quality properties of bread

Water is an ingredient of considerable importance in bread dough. Effects of four different types of electrolyzed water (Anolyte NaCl, Catholyte NaCl, Anolyte Na2CO3, Catholyte Na2CO3) on quality characteristics of bread were investigated. For this aim, rheological and textural analysis of bread doughs and color, physical properties, water activity, moisture content, antioxidant activity, total phenolic content, texture profile analysis, and micrographic analysis of bread samples were performed. Electrolyzed water affected quality characteristics of dough and bread samples significantly (p < 0.05). Anolyte Na2CO3 increased the water-holding capacity of the dough from 60 ± 0.05 to 66 ± 0.07. The bread samples prepared with Anolyte Na2CO3 (363 ± 1.70) and Catholyte Na2CO3 (346 ± 1.61) electrolyzed water has higher loaf volume than the bread samples prepared with Anolyte NaCl (320 ± 1.00) and Catholyte NaCl (310 ± 1.52) electrolyzed water and control bread (270 ± 1.04) (p < 0.05). Electrolyzed water also increased the antioxidant activity (23.62 ± 0.05% inhibition) and total phenolic content (460.61 ± 2.12 GAE/100 g) of bread samples. The results of this study may be evidence that using electrolyzed water can improve the quality characteristics of bread.

Fermentation Kinetics of Gluten-Free Breads: The Effect of Carob Fraction and Water Content

In this study, gluten-free doughs with rice flour, substituted by 15% fractions of different carob seed flours, were prepared by varying their water content. The coarse carob fraction A (median particle size of flour, D₅₀: 258.55 μm) was rich in fibers, fraction B (D₅₀: 174.73 μm) was rich in protein, C (D₅₀: 126.37 μm) was rich in germ protein, and fraction D (D₅₀: 80.36 μm) was a mix, reconstituted from the other fractions and pulverized using a jet mill. Τhe experimental data of the dough's volume over time were fitted to the Gompertz model for each carob fraction and water content. The calculated parameters of the model were the maximum relative volume expansion ratio (a), the maximum specific volume growth rate (μ), and the time lag of the leavening process (t_lag). Gompertz's equation adequately described the individual experimental curves. In the next step, a composite model was applied for each carob fraction where the parameters a and t_lag were expressed as quadratic functions of water content levels (W), while μ was linearly dependent on W. Each carob fraction presented an optimum water content level for which dough height was maximized and time lag was minimized. Optimized dough volume could be predicted by the composite model; it was shifted to lower values as finer carob flour was used. In respect to baked products, softer breads were produced using finer carob flour and porosity values were higher at optimum water content levels. The investigated fermentation kinetics' models provide significant information about the role of water and carob flour on gluten-free dough development and bread volume expansion.

Formation of process contaminants in commercial and homemade deep-fried breadcrumbs

Breading is a culinary technique widespread throughout the world. Deep-frying breaded foods forms a palatable crust but also promotes the formation of compounds of toxicological relevance. The influence of the composition of breadcrumbs on the risk associated with the formation of acrylamide, hydroxymethylfurfural (HMF), and furfural was investigated in a deep-fried breadcrumb coating model. Commercial (CBC) and homemade (HBC) wheat-based breadcrumbs were characterized by the reducing sugars and the asparagine content among other parameters (moisture, pH, and CIELab color). The formation of process contaminants in fried breadcrumbs were not influenced by their initial content, but they were affected by the precursors level. The HMF content was significantly higher (1.4 times) in fried HBC (172 mg/kg) than in CBC (120 mg/kg). By contrast, the acrylamide content was 3 times higher in fried CBC (332 µg/kg) than in HBC (111 µg/kg). Multivariate analysis shows that asparagine is the limiting factor for acrylamide formation, and the reducing sugar content is the main determinant for the formation of furanic compounds. A signal value of 463 µg/kg is proposed for the acrylamide content in the coating of deep-fried breaded foods. The reducing sugars and asparagine content in breadcrumb coatings should be considered when designing breaded foods, thereby reducing the formation and consequently the dietary exposure to these potentially harmful compounds.

Influence of Preferments on the Physicochemical and Sensory Quality of Traditional Panettone

In Peru, panettones are consumed in July and December. The main ingredient of panettones is wheat flour, which can be replaced with substitute flours to improve their nutritional, textural and sensory properties. This study aimed to evaluate the physicochemical, textural and sensory characteristics of panettones produced with three preferments, namely, biga (PB), sourdough (PMM) and sponge (PE), with the substitution of red quinoa flour and amaranth compared with a commercial product (PC). A completely randomized design with four experimental treatments was used to evaluate the total carbohydrate content, ash, total energy, fat, moisture, protein, color and texture profile. In addition, sensory characteristics were evaluated by 80 consumers using the CATA method; the purchase intention and preference ranking were also investigated. The results showed better sensory characteristics of panettones produced with preferments compared with a commercial product with similar characteristics. The sponge preferment presented better sensory characteristics with a profile of sweet, spongy, vanilla odor and moist texture, along with greater acceptability, preference and purchase intention, followed closely by the biga. It was concluded that the sponge preferment presented better sensory properties, which were correlated with its texture profile as manifested by an intermediate hardness, good elasticity and cohesiveness, which translated into greater acceptability, preference and purchase intention.

Study the influence of waxy wheat flour, inulin and guar gum on quality and microstructure of Pita and Tandoori breads: response surface methodology aids functional food development

A diet high in dietary fibre (DF) is thought to help reduce cholesterol levels, may control blood glucose levels and reduces gut transit time. However, people often fail to consume the recommended quantity of DF. The aim of this study was to supplement two types of bread with some novel functional food ingredients; waxy wheat flour (WF), inulin (IN) and guar gum (GG) to develop products rich in DF. Response surface methodology (RSM) was employed to study the effect of DF on two different breads. Breads were assessed using Cryo-SEM for its microstructure pattern, and physical attributes (pita; springiness, chewiness and hardness, Tandoori; hardness and elasticity). The results showed that, for pita bread, the outcome showed that IN and GG alone significantly increased hardness and chewiness and decreased springiness. WF addition only decreased springiness. GG linearly increased pita height and volume, but it quadratically increased weight loss. Moreover, IN increased volume and height in a quadratic way. Regarding Tandoori bread, IN reduced bread toughness, but showed no effect on extensibility. WF alone increased volume and diameter. The microstructure also showed that the novel ingredients modified starch gelatinisation and gluten-starch matrix in both pita and Tandoori breads differently. Therefore, the influence of the three functional ingredients alone and in combinations influenced quality parameters dissimilarly.

The Impact of Waxy Wheat Flour, Inulin and Guar Gum on Post-Prandial Glycaemic and Satiety Indices, Sensory Attributes and Shelf Life of Tandoori and Pita Breads

The purpose of this study was to develop two different functional breads (Pita and Tandoori) supplemented with novel functional ingredients: waxy wheat flour (15%), inulin (8%) and guar gum (2%) independently and in combination. The breads were submitted to sensory characteristics, shelf life, glycaemic and satiety indices assessments. Both guar gum and inulin independently and in combination significantly (p < 0.05) decreased post-prandial blood glucose and glycemic response of Pita (GI of guar gum bread was 55%, inulin 57%) and Tandoori (GI of guar gum bread was 57% and inulin bread was 60%) compared to the control breads (GI 100%). Moreover, the results of the area under the curve of satiety showed that the addition of functional ingredients increased satiety levels as follows: for Pita, control was 355, a combination of all ingredients was 418, inulin was 451 and guar gum was 452; for Tandoori, control was 329, a combination of all ingredients was 420, inulin was 381 and guar gum was 390. The results showed that all sensory characteristics were improved, and breads were acceptable (all obtained more than five points) when the highest proportions of ingredients were added. Similarly, the shelf life of supplemented Pita and Tandoori breads was improved with the addition of ingredients. Therefore, the functional ingredients such as inulin and guar gum can be used independently and in combination to reduce GI and increase satiety of Pita and Tandoori bread with acceptable quality and shelf life.

Chestnut peels and wheat bran at different water level influence the physical properties of pan bread

In breadmaking, dietary fibres are used to improve the nutritional quality of the final products; on the other hand, they may affect the physical and sensory properties. This work aimed to the evaluate, on pan breads, the effect of substituting 3 g of wheat flour with an equivalent amount of fibre rich ingredients: chestnut peels (CP) or wheat bran (WB), in comparison to a traditional wheat bread formulation (C). The effect of four levels of added water (54, 60, 66, 71 g/100 of flour) was also tested. The fibre content of CP (33%) and WB (42%) affected their water binding capacity and, consequently, the quality of the final loaves, according to the different water addition levels. In bread crumb, water content and water activity increased proportionally to the water addition levels, being instead in the crust also affected by the presence of fibres: lower water retention capacity was observed for CP, in comparison to WB and C. The loaf volume resulted higher for C in comparison to WB and CP, in relation to the larger dimensions of the crumb pores, probably due to the interfering effect of fibres during the development of the gluten network. Crumb hardness resulted higher for C at low water addition levels, being instead higher for CP at high water addition levels. CP showed a darker and redder colour, than both WB and C bread, for the presence of the brown pigments carried by chestnut peels. PCA analysis confirmed that more water is required for both the fibre-enriched breads to show characteristics similar to the control loaves.

Consumer acceptability and chemical composition of whole-wheat breads incorporated with brown seaweed (Ascophyllum nodosum) or red seaweed (Chondrus crispus)

BACKGROUND

Seaweeds have been eaten in the diets of coastal cultures for centuries; however, consumption of seaweeds has been limited in Western diets owing to undesirable sensory characteristics and lack of familiarity. Apart from healthful bioactive metabolites, seaweeds are good sources of fibre and minerals. They are nearly a complete protein and have a low fat content (mainly mono- or polyunsaturated). The objectives were (i) to investigate if the addition of brown seaweed, Ascophyllum nodosum, or red seaweed, Chondrus crispus, altered the chemical composition and sensory properties of whole-wheat bread; and (ii) to determine what percentage the addition of brown or red seaweed to whole-wheat bread is acceptable to consumers. The two seaweeds were incorporated into separate batches of whole-wheat bread by percentage weight flour at 0% (control), 2%, 4%, 6%, and 8%.

RESULTS

The products containing the highest amounts of A. nodosum and C. crispus had the highest ash and total dietary fibre. A. nodosum and C. crispus breads were acceptable at 4% and 2% levels respectively. The attributes of no aftertaste, soft, and chewy drove consumer liking of the whole-wheat bread, whereas attributes dry, dense, strong aftertaste, and saltiness detracted from liking.

CONCLUSION

This project's significance is to demonstrate the acceptability of seaweed in a Western population, which may lay the groundwork to encourage and promote the consumption of seaweed or to exemplify seaweed incorporation into foodstuffs. © 2020 Society of Chemical Industry.

Physical and structural characteristics of starch-based and conventional cookies: Water sorption, mechanical glass transition, and texture properties of their crust and crumb

The physical properties of starch-based cookie (gluten free and low fat) were compared with those of conventional cookie in consideration for the difference between crust and crumb parts. The internal porosity of the samples was measured by X-ray computed tomography. The starch-based cookie had a higher porosity (0.61) than the conventional cookie (0.42). The mechanical glass-transition temperature (T_g ) of the samples was evaluated by the thermal rheological analysis. The anhydrous mechanical T_g of the starch-based cookie was much lower than that of the conventional cookie. The T_g -depression of the starch-based cookie induced by water sorption was more gradual than that of the conventional cookie. For both types of cookie, the crust components were more resistant to water plasticizing than crumb components because of the difference of the equilibrium water contents at each water activity. For the texture analysis of crust components, the whole samples were fractured. The starch-based cookie had a lower fracture force, distance, and energy than the conventional cookie at each water activity point. For the texture analysis of crumb components, a portion of the crust was removed from the whole samples, and the exposed crumb was compressed by a plunger. From the texture profile, a normalized linear length was evaluated. The normalized linear length for the starch-based cookie was higher than that for the conventional cookie. These results were corresponded to the differences in the undeveloped gluten and fat contents.

Combined Effect of Chia, Quinoa and Amaranth Incorporation on the Physico-Chemical, Nutritional and Functional Quality of Fresh Bread

With regard to constant technological innovations in the bakery sector in order to increase bread nutritional value without affecting its technological and sensory characteristics, we applied pseudocereals/oilseeds to obtain an optimal formulation. A factorial design 3³ was used and the independent factors were chia flour (levels: 0, 10, 20% flour basis), quinoa flour (levels: 0, 20, 40% flour basis), and amaranth flour (levels: 0, 20, 40% flour basis). Their effects and interactions were studied through the response surface methodology to optimise the bread formulation from a holistic viewpoint, which included the nutritional, technological and sensory characteristics. The optimum formulation with the highest quality was the blend made with 10, 4, and 20% of chia, quinoa, and amaranth, respectively. The results showed a significant increase in protein amount, ash, lipids, and crumb firmness compared to wheat bread. The calorie value of the control sample and the optimised formula were significantly similar, bearing in mind the high lipid amounts present in raw materials. Loaf-specific volume slightly decreased in comparison to control bread, as expected in formulations with gluten-free raw materials and a large amount of fibre. The optimised formula presented nutritionally/functionally higher indexes and similar overall acceptability to the control bread (p < 0.05).

Assessment of Stickiness with Pressure Distribution Sensor Using Offset Magnetic Force

The quantification of stickiness experienced upon touching a sticky or adhesive substance has attracted intense research attention, particularly for application to haptics, virtual reality, and human-computer interactions. Here, we develop and evaluate a device that quantifies the feeling of stickiness experienced upon touching an adhesive substance. Keeping in mind that a typical pressure distribution sensor can only measure a pressing force, but not a tensile force, in our setup, we apply an offset pressure to a pressure distribution sensor and measure the tensile force generated by an adhesive substance as the difference from the offset pressure. We propose a method of using a magnetic force to generate the offset pressure and develop a measuring device using a magnet that attracts magnetic pin arrays and pin magnets; the feasibility of the method is verified with a first prototype. We develop a second prototype that overcomes the noise problems of the first, arising from the misalignment of the pins owing to the bending of the magnetic force lines at the sensor edges. We also obtain measurement results for actual samples and standard viscosity liquids. Our findings indicate the feasibility of our setup as a suitable device for measuring stickiness.

Improving porous crumb structure of rice-related leavened food products by fermentation and gelatinization at slightly higher air pressure conditions

Porous crumb structure of rice-related leavened food products developed under air pressure conditions during fermentation and gelatinization in a fabricated fermentation chamber were characterized. Therein, four samples were prepared under three pressurized conditions (sample pressurized by the leavened gas itself, 1 kg/cm² initial pressure, 1.5 kg/cm² initial pressure) along with a control (unpressurized). Crumb volume, specific volume, bulk density, pH as well as crumb texture profile and cellular structure were analyzed. Results revealed that fermentation and gelatinization under air pressure (slightly higher than the atmospheric air pressure) conditions in the fabricated fermentation chamber help to arrest leavening gas within the dough mass to improve the properties of porous crumb structure. Sample fermented and gelatinized at 1 kg/cm² initial pressure presented better crumb mechanical and cellular structural properties compared to the other two pressurized samples and the control.

Effect of chitosan on physicochemical and rheological attributes of bread

The aim of this study was to develop fiber-enriched functional bread containing selected concentration of chitosan (0.1%, 0.5%, 1%, 1.5%, and 2% w/w). Dynamic rheology of bread dough established that viscous moduli were lower than elastic moduli. Until 1% chitosan concentration, dough extensibility increased. Avrami nonlinear regression equation was selected as a convenient mathematical tool to model bread crumb staling kinetics. Scanning electron microscopy, Fourier-transform infrared, differential scanning calorimetry, and extensibility tests were used to examine the changes of the structure of control dough and chitosan containing dough. Specific volume of bread was inversely proportional to firmness of bread. Firmness is directly proportional function of storage time and chitosan quantity. Sensory evaluation revealed that 1% chitosan can be used as potential functional ingredient to prevent chronic diseases like obesity, type 2 diabetes, constipation, and colon cancer.

Effect of Differently Extracted Arabinoxylan on Gluten-Free Sourdough-Bread Properties

The role of arabinoxylans (AXs) in bread-making has gained interest due to their positive contribution to bread quality. Therefore, the effect of differently extracted (water, alkaline, or enzymatic) rye AXs on gluten-free (GF) buckwheat and millet batter rheology and bread properties was evaluated. The results showed that the addition of AXs influenced most of the batter and bread properties differently, which depended on the chemical and structural properties of the AXs. All batter systems displayed a typical weak gel behavior. Enzyme- (Pentopan Mono BG-) extracted AXs (PEAXs) were able to strengthen both millet and buckwheat batter structures to a greater degree, as seen by the increase in storage modulus. Regarding bread properties, in buckwheat breads, calcium hydroxide-extracted AX (CEAX) was able to improve the specific volume (from 1.73 to 1.93 cm3/g) and firmness (from 10.88 to 4.69 N) the most, compared to the control. The AXs extracted successively with water and the enzyme Pentopan Mono BG (WPEAX) produced the highest loaf volume (2.39 cm3/g) and one of the lowest crumb firmness values (5.51 N) but caused larger pores and a ruptured crust. In millet breads, water-extracted AXs (WEAXs) and CEAX produced lowest crumb hardness (WEAX: 6.94 N; CEAX: 8.53 N). Specific volume was highest in breads with WEAX (2.35 cm3/g), but CEAX displayed a better pore structure. Overall, water-extracted AXs improved the GF bread properties to a higher extent than alkaline-extracted AXs. Only CEAX displayed a comparable effect in some cases, and considering the fact that alkaline extraction of AX is much more efficient (much higher yield), its application compared to other AXs could be more favorable. Overall, AXs hold great potential as baking improvers for GF bread; the extent of their improvement will be defined by their functional properties.

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.

Techno-functional and nutritional performance of commercial breads available in Europe

In recent years, the growing interest for well-being and healthy lifestyle together with an increasing awareness of the close relationship between food and health have boosted the production of an increasing number of novel goods to be placed in both gluten-containing and gluten-free products market. The objective of this study was to provide a realistic and detailed overview of the current bread-market supply in order to evaluate the overall quality of the available offer in this prioritized food industry area. Twenty commercial breads consisting of gluten (n = 10) and gluten-free (n = 10) samples currently available in the European market have been assessed by physical-chemical, technological, nutritional, and sensory determinations. The quality parameters obtained were related to each other by using Pearson correlations, while sample classification was achieved by applying factor analysis. Higher values for protein and bio-accessible polyphenols content, aroma and taste quality, and low and moderate expected glycaemic index corresponded to gluten containing breads. Although the main distinction was between gluten and gluten-free samples as it was expected, classification of breads allowed differentiating samples with different formulations in terms of presence/absence of alternative, innovative, and nutrient-dense raw materials.

Developing a xylanase XYNZG from Plectosphaerella cucumerina for baking by heterologously expressed in Kluyveromyces lactis

Background

Xylanase can replace chemical additives to improve the volume and sensory properties of bread in the baking. Suitable baking xylanase with improved yield will promote the application of xylanase in baking industry. The xylanase XYNZG from the Plectosphaerella cucumerina has been previously characterized by heterologous expression in Pichia pastoris. However, P. pastoris is not a suitable host for xylanase to be used in the baking process since P. pastoris does not have GRAS (Generally Regarded As Safe) status and requires large methanol supplement during the fermentation in most conditions, which is not allowed to be used in the food industry. Kluyveromyces lactis, as another yeast expression host, has a GRAS status, which has been successfully used in food and feed applications. No previous work has been reported concerning the heterologous expression of xylanase gene xynZG in K. lactis with an aim for application in baking.

Results

The xylanase gene xynZG from the P. cucumerina was heterologously expressed in K. lactis. The recombinant protein XYNZG in K. lactis presented an approximately 19 kDa band on SDS-PAGE and zymograms analysis. Transformant with the highest halo on the plate containing the RBB-xylan (Remazol Brilliant Blue-xylan) was selected for the flask fermentation in different media. The results indicated that the highest activity of 115 U/ml at 72 h was obtained with the YLPU medium. The mass spectrometry analysis suggested that the hydrolytic products of xylan by XYNZG were mainly xylobiose and xylotriose. The results of baking trials indicated that the addition of XYNZG could reduce the kneading time of dough, increase the volume of bread, improve the texture, and have more positive effects on the sensory properties of bread.

Conclusions

Xylanase XYNZG is successfully expressed in K. lactis, which exhibits the highest activity among the published reports of the xylanase expression in K. lactis. The recombinant XYNZG can be used to improve the volume and sensory properties of bread. Therefore, the expression yield of recombinant XYNZG can be further improved through engineered strain containing high copy numbers of the XYNZG, and optimized fermentation condition, making bread-baking application possible.

Impact of ancient cereals, pseudocereals and legumes on starch hydrolysis and antiradical activity of technologically viable blended breads

Wheat flour replacement from 22.5% up to 45% by incorporation of ternary blends of teff (T), green pea (GP) and buckwheat (BW) flours provided technologically viable and acceptable sensory rated multigrain breads with superior nutritional value compared to the 100% wheat flour (WT) counterparts. Blended breads exhibited superior nutritional composition, larger amounts of bioaccessible polyphenols, higher anti-radical activity, and lower and slower starch digestibility. Simultaneous lower rapidly digestible starch (57.1%) and higher slowly digestible starch (12.9%) and resistant starch (2.8%) contents (g per 100g fresh bread), considered suitable nutritional trends for dietary starch fractions, were met by the blend formulated 7.5% T, 15% GP, 15% BK. The associated mixture that replaced 37.5% WT, showed a rather lower extent and slower rate of starch hydrolysis with medium-low values for C∞, and H90, and lowest k, and intermediate expected Glycaemic Index (86). All multigrain breads can be labelled as source of dietary fibre (≥ 3 g dietary fibre/100g bread).

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.

Quality parameters of some Brazilian panettones

In panettone, physical and chemical properties can determine the quality attributes in addition to consumer acceptability. The aim of this work was to assess the quality attributes of nine commercial samples of Brazilian panettone. Samples were characterized according to their physicochemical (moisture and color) aspects, quality attributes (specific volume, density and texture) and image analysis. The results of the statistical analysis (ANOVA and Tukey) showed significant differences (p<0.05) among the samples. Differences were observed in the specific volume and density. Samples showed moisture values between 22.83% and 26.86%. The texture analysis showed greater variation in values of crumb firmness (from 2.14 N to 7.55 N). Significant differences in crust (L* values between 31.58 and 44.85, a* between 12.34 and 16.47 and b* between 27.15 and 37.28) and crumb (L* values between 64.48 and 72.34, a* between -0.82 and 3.79 and b* between 33.43 and 40.97) color parameters were found for all samples. Through the image analysis, variability in the crumb structure was observed; however, the statistical analysis showed no significant differences between samples.