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The number of people buying gluten-free breads and baked goods is increasing. To optimise the quality of gluten-free breads, fat and additives are still often used. This project investigated whether the use of particle-stabilised foams could eliminate or at least reduce the need for large amounts of fat and additives in gluten-free toast bread. Hence, particle-stabilised foams were added to bread doughs, kneaded in, baked and then analysed. The breads containing particle-stabilised foams had no significant difference in firmness nor in adhesiveness compared to gluten-free toast bread with additives or to the gluten-containing bread. While the volume of the toast bread containing foam was lower than for the gluten containing reference toast bread, it had up to 2.0–2.5 times the volume than the gluten-free bread reference without additives. These results showed a positive influence of the use of particle-stabilised foams in gluten-free bread without addition of additives.

The roller milling of sorghum and quinoa seeds into flour fractions (coarse, middle, and fine) was investigated, chemically analysed, and applied in the baking of gluten-free sourdough bread. The gap settings were adjusted to 0, 5, 8, and 10 for quinoa, and 3, 5, and 7 for sorghum. The fine fractions reached values of up to about 41% (gap 8) for quinoa and around 20% for sorghum (gap 5). SEM pictographs illustrated the clear separation of each fraction with the chemical analysis showing high contents of protein, TDF (total dietary fibre), and IDF (insoluble dietary fibre) in the coarse fraction. Up to 77% starch content was obtained in the fine fraction with significant amounts of SDF (soluble dietary fibre), which has good health benefits. Increasing the dough moisture up to 90% helped in decreasing the bread crumb firmness, while low Avrami parameters and RVA pasting behaviour indicated a slow bread-staling rate for both sourdough breads.

Wheat is a vital crop in global food security, but up to 25% of the wheat harvested is contaminated with mycotoxins that have detrimental effects on human health. To address this issue, biological detoxification strategies have been developed using microorganisms and enzymes. Perforating the whole wheat kernel using cold needle perforation (CNP) followed by a detoxification step could be a promising approach to reduce cross-contamination during the milling of mycotoxin-containing wheat. In this study, a pilot-scale CNP prototype was developed to perforate wheat kernels, and its effectiveness was evaluated. The height-adjustable perforation unit consists of 3120 needles. The throughput of the CNP prototype was adjusted to 6 kg/h, and the kernels were perforated for 1, 5, or 10 cycles. The results show that the CNP prototype effectively perforates wheat kernels, as evidenced by the significant increase in pore count. Fluorescence microscopy confirmed the penetration of particles in the size range of enzymes and microorganisms into the kernel. This study demonstrates the successful scale-up of CNP for wheat kernel perforation and highlights the potential of CNP as a cost-effective and efficient method for the biological detoxification of mycotoxin-contaminated wheat.

Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch)​, Vacuum cooling of baked goods can deliver many advantages in terms of product quality and productivity, such as higher volumes and shorter cooling times. However, the associated high costs and the need to adjust baking protocols are of relevance and more information is needed. This paper examines the influence of two main baking protocol parameters on the quality of toast bread, i.e. oven temperature and baking time reduction. Resulting toast bread characteristics including specific bread volume, concavity, browning index, crust and crumb hardness and aw-value were analysed as well as process-dependent core temperature and water loss. In order to compensate for water loss during vacuum cooling and still achieve optimal toast bread quality, a final bread core temperature of 98 °C at the end of baking gave best results, regardless of oven temperature. It was further shown that cooling time can be reduced by a factor of 10 if the baking protocol is optimally adjusted, hinting at a huge potential to increase productivity for industrial applications. In summary, it can be stated that vacuum cooling requires a tailored reduction in baking time in order to compensate for water loss from vacuum cooling while retaining sufficient structural cohesion to resist deformation of the bread.

Functional lactic acid bacteria (LAB) as starter cultures used in sourdough fermentation have been researched for years. This study evaluated the LAB strains Leuconostoc citreum DCM65 (mannitol, exopolysaccharide producing, antifungal activity) and Lactiplantibacillus plantarum subsp. plantarum MA418 (amylolytic activity) and their potential as single or co-culture starters in sourdough fermented buns containing different levels of sugar (control 9% and reduced 0, 3, 6%). Cell counts, pH development, and organic acids were determined before and after sourdough fermentation (30 °C, 24 h) and physical properties (color, volume, pore structure, and texture) of buns produced thereof were determined after baking. Sourdoughs started with DCM65 and/or MA418 developed up to log 9.2 CFU/g presumptive LAB after 24 h, assertiveness of the added starter cultures species was confirmed by MALDI-TOF MS. Acetic acid and mannitol were only detected in sourdough fermented with DCM65 (single or co-culture) up to 2.5 mg/g and 9.8 mg/g, respectively. The starter cultures applied influenced physical properties of buns. Sourdough buns started with MA418 had higher volume and slice area, and softer crumb; in contrast, buns fermented with DCM65 had a finer pore structure. In summary, both starter cultures showed high potential in sourdough buns with reduced sugar content.

Palm fat is often used in baked goods because of its relatively low cost, and its positive impact on texture and shelf life. Demand for alternatives has risen in recent years due to concerns about the ecological and social sustainability. This is a challenge for the bakery industry since palm oil possesses unique properties. In this study, unhydrogenated rapeseed oil was processed using novel physical technologies, such as wax crystallisation, stabilized foaming and Pickering emulsions, in order to simulate palm oil properties. Analysis showed that while the initial viscosity of the fat substitute products was low compared to palm fat, the fat replacement products behaved very similarly to palm fat in the baking experiments. The resulting biscuits baked with emulsified rapeseed oil and rapeseed oil complemented with wax crystals were judged to be suitable replacements for palm fat in terms of processability, as well as analytical and sensory assessment.

NaCl is an important contributor to the taste and texture of bread; therefore, it is challenging to reduce NaCl in bread without compromising quality. This study investigated sensory properties of bread with sourdough fermented with Lactobacillus reuteri accumulating glutamate or γ‐aminobutyrate (GABA). Sourdough was fermented with the GABA‐producing L. reuteri 100‐23 and LTH5448 as well as the glutamate‐accumulating L. reuteri 100‐23ΔgadB and TMW1.106. A consumer panel detected significant differences in the taste of bread with 6% addition of sourdough fermented with glutamate‐ or GABA‐producing L. reuteri. Remarkably, this difference was also detected when GABA‐producing L. reuteri 100‐23 was compared with its glutamate‐producing isogenic mutant L. reuteri 100‐23ΔgadB. The intensity of the salty taste of sourdough bread produced with 1% (flour basis) salt was equivalent to the intensity of the salty taste of reference bread produced with 1.5% salt. A trained panel found that sourdough breads (1 or 2% NaCl flour base) had a higher sour and umami taste intensity when compared with reference bread with the same salt content. Bread produced with sourdough fermented with L. reuteri 100‐23ΔgadB consistently had a higher umami taste intensity when compared with other sourdough breads. Neither sourdough addition nor NaCl level influenced bread volume or texture. In conclusion, the use of sourdough fermented with glutamate‐accumulating lactobacilli allowed reduction of NaCl without adverse effects on the taste or other quality attributes of bread.

Some lactic acid bacteria (LAB) are well known for the production of exopolysaccharides (EPS), i.e. homopolysaccharides and heteropolysaccharides. The class of β-glucans comprises a specific group of homopolysaccharides with various positive physiochemical and health promoting aspects. So far, β-glucan production was mainly described in cider spoilage LAB, including Pediococcus parvulus, Oenococcus oeni, and Lactobacillus diolivorans, that were responsible for an undesired alteration of the fermented beverages related to ropiness (1, 2, 3). In contrast to these undesired effects, β-glucan producing LAB incorporated in sourdough may act beneficially on bread quality with benefits in texture and constitutional properties. In this study, we focused on β-glucan production in beneficial LAB isolated from environmental sources with the aim to improve the quality of bakery products by functional microbial metabolites. We therefore selected 83 strains of LAB that were previously isolated from sourdough, fresh baker’s yeast, raw milk, raw and fermented meat, and silage followed by MALDI-TOF MS identification. The screening for β-glucan production was done by a 2-phased strategy described by Werning et al. (2), i.e. an agglutination assay with Streptococcus pneumoniae type 37-specific antisera followed by PCR amplification of a 417-bp fragment of the glycosyltransferase (gtf) gene encoding a β-D-glucan synthase. In doing so, a total of 8 strains belonging to the species Lactobacillus plantarum (3 strains), L. brevis (2 strains), L. paracasei (1 strain), L. mali (1 strain), and Leuconostoc mesenteroides (1 strain) were successfully identified as genotypic β-glucan producers. These strains seem to be very interesting for further application in sourdoughs. First tests including optimization of β-glucan production are currently under investigation.

The first part of this paper has been published in the preceding issue of cereal technology (cereal technol. 70 (1), 2016, pp. 1 - 11). It has been outlined in that part that the measured energy consumption for baking in a rack oven is 1470 kJ/kg of bread. The corresponding energy benchmark (physical minimum) is 745 kJ/kg, 65% of this energy is used for the evaporation of water. The efficiency is calculated by 50.7%. Results showed, that the bread baking process is not efficient, needing twice as much of energy as the calculated benchmark. The objective of sustainable energy management is to optimize the energy consumption of the bread baking process to bring it close to this minimum value. The following Part 2 of this study includes a thermophysical description of the baking process. This model shows the intensity of heat transfer mechanisms by radiation, convection and conduction involved in the baking of bread. Based on the heat transfer model, a total energy of 1167 kJ per kg of bread is used. 70 % is transmitted by radiation, 17 % by convection and 13 % by conduction. Heat transfer decreases heavily by the end of baking due to lower temperature differences.

Vorstellung

Oral presentation, Background and Objectives: Microorganisms and their metabolites produced by biofermentations offer interesting benefits for food applications, e.g. production of specific vitamins; biopreservation and reduction of E-numbers, and improved texture of foods. Two problematic vitamins in nutrition are folate and B12, especially among women of child-bearing age, the aging population and strict vegetarians. This study aimed to develop new, natural sources of these important vitamins as well as other functional substances for adding value to bakery products. Methods: A co-culture technology (a) using strains of Lactobacillus plantarum and Propionibacterium freudenreichii selected for complementary carbon metabolism and high production of folate and Vitamin B12, respectively, was used to produce these vitamins along with anti-microbial compounds, mainly organic acids (propionic, acetic acids and others). The resulting mixture of multifunctional (MF) bio-ingredients was tested in Semmeli breads to assess stability and effects on product quality. Dough, partly- and fully-baked Semmeli were enriched with MF bio-ingredient at 0.1% or 0.2% equivalent propionate, levels shown to exert strong anti-microbial activity in previous work. Results: The MF bio-ingredient contained vitamer 5-formyltetrahydrofolate, known to be metabolically active and shown in baking tests to have higher stability (ca 60% recovery) than endogenous folate (35% recovery) derived from flour. Production of liquid MF ingredient in cereal-based medium using optimal conditions led to levels of folate and B12 as high as ca 6000 ng/ml, and 1000 ng/ml, respectively. Most bread-making and final quality determinations were acceptable for industry applications, as shown by physico-chemical, texture and sensory analyses. Conclusions: This co-culture technology and MF bio-ingredients have good potential for natural food fortification, allowing to reach or exceed vitamin levels required for EU authorized health claims. In

Baking is an energy-intensive process including substantial losses. Increasing energy efficiency not only helps to slow down climate change, but also reduces the amount of money spent on primary energy. The objective of this study was to compare different methods of determining the energy consumption during the bread baking process. In the first part, energy consumption was measured experimentally in an electrically heated rack oven. The difference between standard trials and trials with no product in the oven identified the energy absorbed by the bread and trials with the empty oven demonstrated the total energy loss. The second part of this study incorporated a specific calculation to determine how much energy is required to raise the temperature of the bread and dry the crust. This value, called benchmark, described the minimum energy requirement. The measured energy consumption for baking in a rack oven is 1470 kJ/kg of bread. The corresponding energy benchmark (physical minimum) is 745 kJ/kg, 65% of this energy is used for the evaporation of water. The efficiency is calculated by 50.7%. Results showed that the bread baking process is not efficient, needing twice as much of energy as the calculated benchmark. The objective of sustainable energy management is to optimize the energy consumption of the bread baking process to bring it close to this minimum value.