Use of Biotechnology to increase the content of bioactive compounds in fermented foods of plant origin

The objectives of this PhD research were: i) to evaluate the use of bread making process to increase the content of β-glucans, resistant starch, fructans, dietary fibers and phenolic compounds of kamut khorasan and wheat breads made with flours obtained from kernels at different maturation stage (at milky stage and fully ripe) and ii) to study the impact of whole grains consumption in the human gut. The fermentation and the stages of kernel development or maturation had a great impact on the amount of resistant starch, fructans and β-glucans as well as their interactions resulted highly statistically significant. The amount of fructans was high in kamut bread (2.1g/100g) at the fully ripe stage compared to wheat during industrial fermentation (baker’s yeast). The sourdough increases the content of polyphenols more than industrial fermentation especially in bread made by flour at milky stage. From the analysis of volatile compounds it resulted that the sensors of electronic nose perceived more aromatic compound in kamut products, as well as the SPME-GC-MS, thus we can assume that kamut is more aromatic than wheat, so using it in sourdough process can be a successful approach to improve the bread taste and flavor. The determination of whole grain biormakers such as alkylresorcinols and others using FIE-MS AND GC-tof-MS is a valuable alternative for further metabolic investigations. The decrease of N-acetyl-glucosamine and 3-methyl-hexanedioic acid in kamut faecal samples suggests that kamut can have a role in modulating mucus production/degradation or even gut inflammation. This work gives a new approach to the innovation strategies in bakery functional foods, that can help to choose the right or best combination between stages of kernel maturation-fermentation process and baking temperature.

Developments and Microbiological applications in African foods: Emphasis on Nigerian Wara cheese

African indigenous foods have received limited research. Most of these indigenous foods are fermented and they form part of the rich nutritional culture of many groups in African countries. The industrialization and commercialisation of these indigenous African fermented foods should be preceded by a thorough scientific knowledge of their processing which can be vital in the elimination of hunger and poverty. This study highlighted emerging developments and the microbiology of cereal-based and cassava-based food products that constitute a major part of the human diet in most African countries. In addition, investigations were also carried out on the coagulant of the Calotropis procera plant used in traditional production of Nigerian Wara cheese and on the effects of adding a nisin producing Lactococcus lactis strain originating from human milk to Nigerian Wara cheese. Fermented cereal-based food such as ogi utilize popular African and readily available grains maize, millet or sorghum as substrates and is popular as a weaning diet in infants. In this study, the bulkiness caused by starch gelatinization was solved by amylase treatments in the investigation on cooked and fermented oat bran porridge. A similar treatment could reduce the viscosity of any cereal porridge. The properties of the Sodom apple leaves (Calotropis procera) extract in cheesemaking were studied. C. procera was affected by monovalent (K+ and Na+) and divalent (Mg2+ and Ca2+) cations during coagulation. The rennet strength of this coagulant was found to be 7 % compared to animal rennet at 35 °C. Increasing the incubation temperature to 70 °C increased the rennet strength 28-fold. The molecular weight of the partially purified protease was determined by SDS-PAGE and was confirmed by Zymography to be approximately 60 kilodaltons. The high proteolytic activity at 70 °C supported the suitability of the protease enzyme as a coagulant in future commercial production of Nigerian Wara cheese. It was also possible to extend the shelf life of Wara cheese by a nisin producing lactic acid bacteria Lactococcus lactis LAC309. The levels of nisin in both whey and curd fractions of Wara were investigated, results showed a 3 log reduction of toxicogenic Bacillus licheniformis spiked on Wara after 3 days. These studies are the first in Finland to promote the advancement of scientific knowledge in African foods. Recognizing these indigenous food products and an efficient transfer of technology from the developed countries to industrialize them are necessary towards a successful realization of the United Nations Millenium Development Program.

Optimisation of oat milk formulation to obtain fermented derivatives by using probiotic Lactobacillus reuteri microorganisms

Functional advantages of probiotics combined with interesting composition of oat were considered as an alternative to dairy products. In this study, fermentation of oat milk with Lactobacillus reuteri and Streptococcus thermophilus was analysed to develop a new probiotic product. Central composite design with response surface methodology was used to analyse the effect of different factors (glucose, fructose, inulin and starters) on the probiotic population in the product. Optimised formulation was characterised throughout storage time at 4 ℃ in terms of pH, acidity, β-glucan and oligosaccharides contents, colour and rheological behaviour. All formulations studied were adequate to produce fermented foods and minimum dose of each factor was considered as optimum. The selected formulation allowed starters survival above 107/cfu ml to be considered as a functional food and was maintained during the 28 days controlled. β-glucans remained in the final product with a positive effect on viscosity. Therefore, a new probiotic non-dairy milk was successfully developed in which high probiotic survivals were assured throughout the typical yoghurt-like shelf life.

Structure, function, and phylogeny of the mating locus in the Rhizopus oryzae complex.

The Rhizopus oryzae species complex is a group of zygomycete fungi that are common, cosmopolitan saprotrophs. Some strains are used beneficially for production of Asian fermented foods but they can also act as opportunistic human pathogens. Although R. oryzae reportedly has a heterothallic (+/-) mating system, most strains have not been observed to undergo sexual reproduction and the genetic structure of its mating locus has not been characterized. Here we report on the mating behavior and genetic structure of the mating locus for 54 isolates of the R. oryzae complex. All 54 strains have a mating locus similar in overall organization to Phycomyces blakesleeanus and Mucor circinelloides (Mucoromycotina, Zygomycota). In all of these fungi, the minus (-) allele features the SexM high mobility group (HMG) gene flanked by an RNA helicase gene and a TP transporter gene (TPT). Within the R. oryzae complex, the plus (+) mating allele includes an inserted region that codes for a BTB/POZ domain gene and the SexP HMG gene. Phylogenetic analyses of multiple genes, including the mating loci (HMG, TPT, RNA helicase), ITS1-5.8S-ITS2 rDNA, RPB2, and LDH genes, identified two distinct groups of strains. These correspond to previously described sibling species R. oryzae sensu stricto and R. delemar. Within each species, discordant gene phylogenies among multiple loci suggest an outcrossing population structure. The hypothesis of random-mating is also supported by a 50:50 ratio of plus and minus mating types in both cryptic species. When crossed with tester strains of the opposite mating type, most isolates of R. delemar failed to produce zygospores, while isolates of R. oryzae produced sterile zygospores. In spite of the reluctance of most strains to mate in vitro, the conserved sex locus structure and evidence for outcrossing suggest that a normal sexual cycle occurs in both species.

Intake of dairy products in relation to periodontitis in older Danish adults

This cross-sectional study investigates whether calcium intakes from dairy and non-dairy sources, and absolute intakes of various dairy products, are associated with periodontitis. The calcium intake (mg/day) of 135 older Danish adults was estimated by a diet history interview and divided into dairy and non-dairy calcium. Dairy food intake (g/day) was classified into four groups: milk, cheese, fermented foods and other foods. Periodontitis was defined as the number of teeth with attachment loss ≥3 mm. Intakes of total dairy calcium (Incidence-rate ratio (IRR) = 0.97; p = 0.021), calcium from milk (IRR = 0.97; p = 0.025) and fermented foods (IRR = 0.96; p = 0.03) were inversely and significantly associated with periodontitis after adjustment for age, gender, education, sucrose intake, alcohol consumption, smoking, physical activity, vitamin D intake, heart disease, visits to the dentist, use of dental floss and bleeding on probing, but non-dairy calcium, calcium from cheese and other types of dairy food intakes were not. Total dairy foods (IRR = 0.96; p = 0.003), milk (IRR = 0.96; p = 0.028) and fermented foods intakes (IRR = 0.97; p = 0.029) were associated with reduced risk of periodontitis, but cheese and other dairy foods intakes were not. These results suggest that dairy calcium, particularly from milk and fermented products, may protect against periodontitis. Prospective studies are required to confirm these findings.

Probiotics and prebiotics: prospects for public health and nutritional recommendations

Probiotics and prebiotics are useful interventions for improving human health through direct or indirect effects on the colonizing microbiota. However, translation of these research findings into nutritional recommendations and public health policy endorsements has not been achieved in a manner consistent with the strength of the evidence. More progress has been made with clinical recommendations. Conclusions include that beneficial cultures, including probiotics and live cultures in fermented foods, can contribute towards the health of the general population; prebiotics, in part due to their function as a special type of soluble fiber, can contribute to the health of the general population; and a number of challenges must be addressed in order to fully realize probiotic and prebiotic benefits, including the need for greater awareness of the accumulated evidence on probiotics and prebiotics among policy makers, strategies to cope with regulatory roadblocks to research, and high-quality human trials that address outstanding research questions in the field.

Cancer risk assessment of ethyl carbamate in alcoholic beverages from Brazil with special consideration to the spirits cachaca and tiquira

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Botulismo de origem alimentar

O botulismo alimentar ocorre pela ingestão de toxinas pré-formadas pelo Clostridium botulinum, consideradas as mais potentes dentre as toxinas conhecidas. Caracteriza-se como uma doença de extrema gravidade, de evolução aguda, provoca distúrbios digestivos e neurológicos, em conseqüência à ingestão de diversos tipos de alimentos. As conservas caseiras estão entre os alimentos que oferecem maior risco à população consumidora. Os produtos de origem animal são frequentemente associados aos surtos da doença, destacando-se os embutidos, tais como salsichas, salames, presuntos e patês. Derivados do leite e enlatados, bem como produtos fermentados, são passíveis de provocar a intoxicação. As outras formas naturais da doença são botulismo por feridas e botulismo infantil, normalmente associado ao consumo de mel contendo esporos do Clostridium botulinum.

Determination of ethyl carbamate in cachaça produced from copper stills by HPLC

Ethyl carbamate (EC) is a common substance in fermented foods and drinks, and its quantification is important because of its carcinogenic nature and its usually presence in alcoholic beverages. The present work involved the development and validation of an analytical method for the evaluation of EC in cachaça by HPLC-FLD after previous derivatization with xanthydrol. The method presented a mean recovery of 94.88%, an intra-day precision of 4.19% (30.0 μg L−1) and 3.32% (75.0 μg L−1), a coefficient of determination (r2) equal to 0.9985, and limits of detection and quantification equal to 6.39 and 21.32 μg L−1, respectively. The results show that the analytical method is accurate, reproducible and linear over the concentration range from 5.0 to 160 μg of EC per litre. The method was applied to the analysis of EC in cachaça, the analyses being rapid and efficient.

Nutrição de operárias de uruçu-amarela, Melipona flavolineata Friese, 1900 (Apidae: Meliponina)

A criação de abelhas sem ferrão é antiga nas Américas. No entanto, a atividade ainda esta subdesenvolvida, necessitando de melhorias nas técnicas de manejo. Este estudo avaliou alternativas nutricionais para a abelha amazônica Melipona flavolineata, visando substituição da alimentação com mel e pólen fermentado. As seguintes alternativas nutricionais foram comparadas com o mel (T1): xarope de açúcar invertido com minerais (T2) e este xarope acrescido de solução de aminoácidos e vitaminas nas seguintes concentrações: 0,5% (T3), 1,0% (T4) e 10% (T5). Ao pólen fermentado (T1) foram comparados alimentos fermentados com inóculo de pólen fermentado de M. flavolineata, constituídos de: pólen apícola (T2); levedo (T3); e extrato de soja, em duas diferentes concentrações de proteínas (T4, 12% e T5, 18%). O valor nutricional das dietas foi baseado no consumo diário, no peso das operárias, no tamanho dos acinos das glândulas hipofaringeas e no tamanho dos oócitos. Avaliaram-se, tambem, os custos dos ingredientes das dietas. Os resultados obtidos indicaram que dentre as alternativas para o mel, não houve diferenças estatísticas entre o controle e todos os tratamentos. Foram encontradas diferenças apenas entre os tamanhos dos acinos das operárias alimentadas com os tratamentos 2 e 4, sendo o tratamento 4 superior. Os custos dos ingredientes indicaram o tratamento 2 como sendo mais barato que os demais. Dentre as alternativas para o sabura foram encontradas maiores diferenças. O consumo do tratamento 4 foi significativamente superior ao do T3, indicando maior aceitação do extrato de soja em relação ao levedo. Em relação aos demais parâmetros avaliados, o tratamento 5 foi superior a todos os demais e seu custo foi muito inferior ao do T2 e semelhante ao dos T3 e T4. Concluiu-se que as melhores alternativas para a nutrição de M. flavolineata sao o xarope de acucar invertido com minerais, e o pólen fermentado semi-artificial à base de extrato de soja. Colônias recém-formadas, com 500-600 abelhas, devem receber 10 a 20 ml de xarope e 25 g de pólen fermentado semi-artificial semanalmente.

Catabolic flexibility of mammalian-associated lactobacilli

Metabolic flexibility may be generally defined as “the capacity for the organism to adapt fuel oxidation to fuel availability”. The metabolic diversification strategies used by individual bacteria vary greatly from the use of novel or acquired enzymes to the use of plasmid-localised genes and transporters. In this review, we describe the ability of lactobacilli to utilise a variety of carbon sources from their current or new environments in order to grow and survive. The genus Lactobacillus now includes more than 150 species, many with adaptive capabilities, broad metabolic capacity and species/strain variance. They are therefore, an informative example of a cell factory capable of adapting to new niches with differing nutritional landscapes. Indeed, lactobacilli naturally colonise and grow in a wide variety of environmental niches which include the roots and foliage of plants, silage, various fermented foods and beverages, the human vagina and the mammalian gastrointestinal tract (GIT; including the mouth, stomach, small intestine and large intestine). Here we primarily describe the metabolic flexibility of some lactobacilli isolated from the mammalian gastrointestinal tract, and we also describe some of the food-associated species with a proven ability to adapt to the GIT. As examples this review concentrates on the following species - Lb. plantarum, Lb. acidophilus, Lb. ruminis, Lb. salivarius, Lb. reuteri and Lb. sakei, to highlight the diversity and inter-relationships between the catabolic nature of species within the genus.

Bebida láctea caprina com suco de uva potencialmente probiótica: viabilidade de cepas de Lactobacillus rhamnosus e aceitabilidade sensorial.

Ojetivou-se desenvolver uma bebida láctea fermentada caprina adicionada de suco integral de uva, utilizando duas cepas de Lactobacillus rhamnosus, uma comercial e outra nativa, isolada a partir de queijos artesanais e selecionada em função de propriedades probióticas e tecnológicas .

The manufacture of preserved foods and sweetmeats; a handbook of all the processes for the preservation of flesh, fruit, and vegetables, and for the preparation of dried fruit, dried vegetables, marmalades, fruit-syrups, and fermented beverages, and of all kinds of candies, candied fruit, sweetmeats, rocks, drops, dragées, pralines, etc.,

Mode of access: Internet.

Fundamental studies of sourdoughs fermented with Weissella cibaria and Lactobacillus plantarum: influence on baking characteristics, sensory profiles and in vitro starch digestibility of gluten-free breads

The application of sourdough can improve texture, structure, nutritional value, staling rate and shelf life of wheat and gluten-free breads. These quality improvements are associated with the formation of organic acids, exopolysaccharides (EPS), aroma or antifungal compounds. Initially, the suitability of two lactic acid bacteria strains to serve as sourdough starters for buckwheat, oat, quinoa, sorghum and flours was investigated. Wheat flour was chosen as a reference. The obligate heterofermentative lactic acid bacterium (LAB) Weissella cibaria MG1 (Wc) formed the EPS dextran (a α-1,6-glucan) from sucrose in situ with a molecular size of 106 to 107 kDa. EPS formation in all breads was analysed using size exclusion chromatography and highest amounts were formed in buckwheat (4 g/ kg) and quinoa sourdough (3 g/ kg). The facultative heterofermentative Lactobacillus plantarum FST1.7 (Lp) was identified as strong acidifier and was chosen due to its ubiquitous presence in gluten-free as well as wheat sourdoughs (Vogelmann et al. 2009). Both Wc and Lp, showed highest total titratable acids in buckwheat (16.8 ml; 26.0 ml), teff (16.2 ml; 24.5 ml) and quinoa sourdoughs (26.4 ml; 35.3 ml) correlating with higher amounts of fermentable sugars and higher buffering capacities. Sourdough incorporation reduced the crumb hardness after five days of storage in buckwheat (Wc -111%), teff (Wc -39%) and wheat (Wc -206%; Lp -118%) sourdough breads. The rate of staling (N/ day) was reduced in buckwheat (Ctrl 8 N; Wc 3 N; Lp 6 N), teff (Ctrl 13 N; Wc 9 N; Lp 10 N) and wheat (Ctrl 5 N; Wc 1 N; Lp 2 N) sourdough breads. Bread dough softening upon Wc and Lp sourdough incorporation accounted for increased crumb porosity in buckwheat (+10.4%; +4.7), teff (+8.1%; +8.3%) and wheat sourdough breads (+8.7%; +6.4%). Weissella cibaria MG1 sourdough improved the aroma quality of wheat bread but had no impact on aroma of gluten-free breads. Microbial shelf life however, was not prolonged in any of the breads regardless of the starter culture used. Due to the high prevalence of insulin-dependent diabetes mellitus particular amongst coeliac patients, glycaemic control is of great (Berti et al. 2004). The in vitro starch digestibility of gluten-free breads with and without sourdough addition was analysed to predict the GI (pGI). Sourdough can decrease starch hydrolysis in vitro, due to formation of resistant starch and organic acids. Predicted GI of gluten-free control breads were significantly lower than for the reference white wheat bread (GI=100). Starch granule size was investigated with scanning electron microscopy and was significantly smaller in quinoa flour (<2 μm). This resulted in higher enzymatic susceptibility and hence higher pGI for quinoa bread (95). Lowest hydrolysis indexes for sorghum and teff control breads (72 and 74, respectively) correlate with higher gelatinisation peak temperatures (69°C and 71°C, respectively). Levels of resistant starch were not increased by addition of Weissella cibaria MG1 (weak acidifier) or Lactobacillus plantarum FST1.7 (strong acidifier). The pGI was significantly decreased for both wheat sourdough breads (Wc 85; Lp 76). Lactic acid can promote starch interactions with gluten hence decreasing starch susceptibility (Östman et al. 2002). For most gluten-free breads, the pGI was increased upon sourdough addition. Only sorghum and teff Lp sourdough breads (69 and 68, respectively) had significantly decreased pGI. Results suggest that the increase of starch hydrolysis in gluten-free breads was related to mechanism other than presence of organic acids and formation of resistant starch.

Selection of potential probiotic lactic acid bacteria from fermented olives by in vitro tests

The present study aims to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from naturally fermented olives and select candidates to be used as probiotic starters for the improvement of the traditional fermentation process and the production of newly added value functional foods. Seventy one (71) lactic acid bacterial strains (17 Leuconostoc mesenteroides, 1 Ln. pseudomesenteroides, 13 Lactobacillus plantarum, 37 Lb. pentosus, 1 Lb. paraplantarum, and 2 Lb. paracasei subsp. paracasei) isolated from table olives were screened for their probiotic potential. Lb. rhamnosus GG and Lb. casei Shirota were used as reference strains. The in vitro tests included survival in simulated gastrointestinal tract conditions, antimicrobial activity (against Listeria monocytogenes, Salmonella Enteritidis, Escherichia coli O157:H7), Caco-2 surface adhesion, resistance to 9 antibiotics and haemolytic activity. Three (3) Lb. pentosus, 4 Lb. plantarum and 2 Lb. paracasei subsp. paracasei strains demonstrated the highest final population (>8 log cfu/ml) after 3 h of exposure at low pH. The majority of the tested strains were resistant to bile salts even after 4 h of exposure, while 5 Lb. plantarum and 7 Lb. pentosus strains exhibited partial bile salt hydrolase activity. None of the strains inhibited the growth of the pathogens tested. Variable efficiency to adhere to Caco-2 cells was observed. This was the same regarding strains' susceptibility towards different antibiotics. None of the strains exhibited β-haemolytic activity. As a whole, 4 strains of Lb. pentosus, 3 strains of Lb. plantarum and 2 strains of Lb. paracasei subsp. paracasei were found to possess desirable in vitro probiotic properties similar to or even better than the reference probiotic strains Lb. casei Shirota and Lb. rhamnosus GG. These strains are good candidates for further investigation both with in vivo studies to elucidate their potential health benefits and in olive fermentation processes to assess their technological performance as novel probiotic starters.