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Highlights: [•] Gac can be an interesting and stable source of all-trans-lycopene. [•] Isomerization by heat treatment made gac lycopene solution more antioxidant. [•] Heat process provoked isomerization to, successively, 15-, 13- and 9-cis-lycopene. [•] 9-cis-Lycopene was more antioxidant than all-trans- and 13-cis-lycopene. [•] Spectral ratios can be a simple marker of lycopene isomerization. [ABSTRACT FROM AUTHOR]

Abstract: Based on bioinformatic data on model fungi, the rodA and wetA genes encoding, respectively, a RodA hydrophobin protein and the WetA protein involved in conidiation mechanisms, were PCR-cloned and characterized for the first time in Penicillium camemberti. These results, completed by a sequence of the brlA gene (available in GenBank), which encodes a major transcriptional regulator also involved in the conidiation mechanism, were used to compare, by qRT-PCR, the expression of the three genes in liquid and solid cultures in a synthetic medium. While expression of the brlA and wetA genes increased dramatically in both culture conditions after 4 days of growth, expression of the rodA gene increased only with conidiation and in the solid culture, and this expression was correlated with production and secretion of a RodA protein outside the hyphae, which became very hydrophobic. In liquid cultures, no production of RodA occurred in mycelia, which remained hydrophilic, and no conidiation was detected despite formation of swellings at the tips of hyphae. The absence of conidiation in liquid culture correlated with the lack of rodA gene expression, which could be regulated by the medium composition independently of brlA and wetA genes expression. [Copyright &y& Elsevier]

Abstract: The aroma compound β-ionone can be produced in a biotechnological way yielding the “natural” label by using enzyme-generated reactive oxygen species. To improve the process, different ways of presenting the hydrophobic substrate β-carotene to these species were investigated using micelles dispersed in water or solvent. β-Carotene had to be present in the aqueous phase to be cleaved and the degradation was more rapid for surfactants exhibiting hydrophile/lipophile balance values around 12–15 (about 80–90% degradation after 3h) than for values inferior to 8 (less than 40% degradation). The presence of an organic phase was useful to increase the stability of lipoxygenase. [Copyright &y& Elsevier]

Abstract: β-Carotene (BC) exhibits controversial antioxidant properties as it may act also as a prooxidant. Its stability toward oxidation depends on its dispersion form and can be increased through encapsulation. In this study, oxidation of BC from synthetic and natural origins was investigated after dispersion in Tween micelles or poly lactic acid (PLA) particles. Two oxidation systems were used: autooxidation and oxidation by xanthine oxidase-generated-reactive oxygen species. Results showed that synthetic BC formed nanometric negatively-charged particles in both Tween micelle and PLA systems, whereas the natural BC sample used was shown to be already pre-oxidised, forming micrometric-uncharged aggregates in Tween micelles and nanosize PLA particles. Samples also displayed different type of supramolecular aggregation (H or J), as shown in their UV–vis spectra, which were related to their particle size and their origin. Natural BC-loaded Tween micelles displayed high absorption in the range 350–450nm (absorption of oxidation products) and rapid autodegradation rate which could reflect a high prooxidant activity. Interestingly, these properties were both significantly reduced with PLA encapsulation. Furthermore, the degradation rate and the oxidation product apparition of the two BC forms could be related to the supramolecular structure adopted by BC during dispersion. [ABSTRACT FROM AUTHOR]

Yeasts are good materials for encapsulation of actives, but, as they are preformed capsules, they have to be loaded. Our goal was to load cells with a big and very hydrophobic molecule, β-carotene (LogP ≈15). In classical conditions, the entry of this compound into cells is negligible and we have worked on ways to favor the entry through the cell wall. Carotene was prepared at 0.3–3 g L −1 in solvents to improve solubility and alter the cell wall structure. After a 3 h-incubation of cells with this solution, with the apolar hexane, the entry was increased to 95 μg g −1  cell wet weight but the monopolar chloroform was much more efficient (220 μg g −1  cell wet weight). However, increasing the carotene concentration in chloroform increased the adhesion of carotene on the cell wall (over 900 μg g −1  cell wet weight) but did not increase the amount into the cell. The use of ultrasound (6-min-treatment at 50% and an output control of 4) as a green physical treatment increased significantly the result for β-carotene encapsulation (852 μg g −1  cell wet weight). [ABSTRACT FROM AUTHOR]

Hibiscus sabdariffa extracts, a rich source of anthocyanin, were subjected to encapsulation in yeast cells. An encapsulation yield (EY) of 208 μg/100 mg of cells and an encapsulation efficiency (EE) of 27%, were reached after optimisation of the ratios (0.5 g wet yeast cells for 5 ml of anthocyanin extracts at 1 g·L −1 ) and with 10% of ethanol. The storage stability of encapsulated pigments was investigated in water and buffer pH 1.5 at 5 & 37 °C for 10 days and 90 °C for 30 min. The percentage of loss of colour was determined by colourimetry assays. The microparticles made of yeast with or without heat treatment exhibited different protecting effects ( P  < 0.01). At 37 °C, the percentage of loss of colour in water was of 2.5% for heat-treated and 36.5% for non-treated yeast microparticles, suggesting that yeast enzymes would be responsible for the loss of anthocyanin during storage. These results are confirmed by the percentage of loss of colour which was far lower in conditions of low enzymatic activity: 3.1% at 5 °C for non-heat-treated cells in water. The pH of solvent had also an important effect on the degradation of encapsulated anthocyanin; in buffer at pH 1.5 and 37 °C with the non-heat-treated cells, the degradation decreased strongly to 9.4% compared with 36.5% in water. These results show that yeast cells are a good mean of encapsulation of pigments for a colouring purpose and that they provide anthocyanins a good protection as long as their enzymes are inactivated. [ABSTRACT FROM AUTHOR]

The production of γ-decalactones as aroma compounds is highly dependent on the access of the biocatalyst to substrate and co-substrate (oxygen). In this work, the potential of solid state fermentation (SSF) is investigated for this production with Y. lipolytica W29. Luffa sponge was used as an inert support and the investigation focused on the impact of aeration on metabolites. In that goal, experiments were carried out in three different SSF reactor types, wide-mouth Erlenmeyer flask (static aeration), forced aeration mini-reactor, and small-headspace bottle (without aeration). Four lactones were detected by GC–MS during the degradation of ricinoleic acid from castor oil by Y. lipolytica W29: 3-hydroxy-γ-decalactone, which reached the high concentration of 5 g/L (in wide-mouth Erlenmeyer flask), γ-decalactone, dec-2-en-4-olide and dec-3-en-4-olide. In this study, some yeast cells changed their morphological properties from the yeast-like shape to pseudo-mycelium and mycelium. These cells may undergo a metabolic shift resulting in the high production of 3-hydroxy-γ-decalactone. The yield of lactone in the small-headspace bottle was very low suggesting insufficient oxygen availability. For their part, forced-aeration conditions in mini-reactors resulted in the stripping of lactone compounds. From the present work, an alternative process is proposed as a novel model for lactone production. [ABSTRACT FROM AUTHOR]

Extraction of bioactives is a cause of structural changes in these molecules. In this work, the bioactivity of commercial natural β-carotenes, one softly extracted without heat-assistance from Momordica cochinchinensis (BCG), one conventionally extracted from another natural source (BCC), and a synthetic one (BCS), was assessed during an additional heat-treatment mimicking formulation. Their antioxidant activities were evaluated after heat-treatment at different concentrations through hemolysis of horse red blood cells. The thermal 15- cis -isomerization of β-carotene, characterized by DAD–HPLC, resulted in a 2.5- to 4.8-fold increase in the anti-hemolytic effect but this was undetected in chemical assay, at 4 μM. At 100 μM, BCC lost its antioxidant properties and became pro-oxidant. This effect might be caused by long-chain-oxidized-products of BCC. Results demonstrated that a short heat-treatment improves the bioactivity of β-carotene but longer treatments made BCC prooxidant, showing that samples that underwent drastic extraction processes could not tolerate additional steps for functional food production. [ABSTRACT FROM AUTHOR]

Decalactones are interesting flavouring compounds that can be produced from ricinoleic acid. In this study, the production of lactones in biofilms using Yarrowia lipolytica is investigated. The hydrophobia of cells increased for increased aeration rates resulting in higher adhesion when the reactor wall was hydrophobic (plastic). To increase adhesion, sheets of methyl-polymethacrylate (PMMA) were added in the reactor and the production of lactones increased with the surface of plastic added, reaching 850mg/L of 3-hydroxy-γ-decalactone for 60cm2. In an Airlift bioreactor made of PMMA, biofilms were present at the top of the reactor for increased aeration. In the meantime, a metabolic shift occurred resulting in high amounts of 3-hydroxy-γ-decalactone. At 0.493vvm and 61h of culture, the dissolved oxygen ratio was of 28.6% and cells grew to only 1.29×106cells/mL in the liquid medium but 3-hydroxy-γ-decalactone accumulated to 1.7g/L instead of less than 0.3mg/L for lower aeration. Adhering cells had a particular elongated shape intermediate between the yeast and the pseudofilamentous forms. It is concluded that adhering Y. lipolytica cells are in a specific physiological state changing their structure but also their metabolic properties and these properties make them good candidate for simple immobilisation process. [ABSTRACT FROM AUTHOR]

Abstract: Momordica cochinchinensis, so-called gấc in Vietnam, is considered as a fruit with high nutritional potential. Its antioxidant property, due to a high concentration of carotenes (β-carotene and lycopene), is particularly estimated. In this study, we have investigated the degradation of carotene extracts obtained from gấc aril. These extracts were dispersed in the aqueous phase in Tween 80 micelles or were encapsulated into polylactic acid (PLA) particles. In both cases, carotenes were far less degraded than synthetic β-carotene. However, the degradation of lycopene was still rapid (around 1mM lycopene degraded per hour), whereas β-carotene was almost not bleached. Moreover, in gấc, the cleavage of the β-carotene''s molecule was situated nearer the extremity of the cycle than for pure β-carotene. It gave rise essentially to β-cyclocitral. For encapsulated β-carotene, the presence of PLA modified this site to the C9-10 bond which is the favoured cleavage site of pure β-carotene. We conclude that the presence of lycopene in gấc has a protective role on the molecule of β-carotene and modifies the cleavage site. However, the supramolecular structure is still very important in the orientation of cleavage as the encapsulation in PLA particles increases degradation and modifies the cleavage site. [Copyright &y& Elsevier]

Abstract: The effect of antimicrobial sodium caseinate-based films was investigated on inhibition of Listeria innocua in cheese. Nisin was incorporated into sorbitol-plasticized sodium caseinate films at 1000IU/cm2 and the films were prepared by casting methods. Mini red Babybel® cheese was chosen as a semi-soft cheese model. The antimicrobial activity was studied based on the contact between antimicrobial films and surface-contaminated as well as in-depth contaminated cheese samples during a 7-day storage at 4°C. The active films produced resulted in a reduction of 1.1 logCFU/g reduction in L. innocua counts in surface-inoculated cheese samples after 1week of storage as compared to control samples. Regarding in-depth inoculated cheese samples, antimicrobial effectiveness was found to be dependent on the distance from the contact surface with the films containing nisin to the cheese matrix. The inactivation rates obtained were 1.1, 0.9 and 0.25 logCFU/g with slice 1 (distance from contact surface d =1mm), slice 2 (d =2mm) and slice 3 (d =3mm), respectively. Our study demonstrates the potential application of antimicrobial films as a promising method to overcome problems associated with post-process contamination, thus enhancing the safety and extending the shelf life of food products. [Copyright &y& Elsevier]

Abstract: Cell localisation in the matrix microstructure of fermented food is important for microbial activity and ripening. To evaluate the importance of physicochemical factors in these phenomena, the physicochemical behaviour of four strains of lactic acid bacteria were investigated after inoculation of raw milk or milk fractions. To discriminate between physicochemical and metabolic properties, media were (i) rapidly acidified to avoid cell division or (ii) bacteria were allowed to ferment milk. To evaluate the impact of milk components, cells were dispersed in protein or fatty globule fractions. From two Lactococcus lactis subsp. lactis biovar. diacetylactis strains selected from their different surface properties investigated in previous studies, after rapid acidification one was encountered in fatty globules and protein gels whereas the other was found in serum and on the surface of globules. After fermentation, the first one formed colonies in the lipid phase or next to it in the whey and the second formed colonies in the protein gel. Strains forming long chains (Lactobacillus bulgaricus and Streptococcus thermophilus) were always found in contact with fatty globules, where they developed. Our results suggest that localisation and subsequent spatial colonisation depend on the physicochemical properties of cell surfaces, on the structure in chains as well as on the metabolic ability to develop on proteins or lipids. [ABSTRACT FROM AUTHOR]

Fermented Asian foods have recently gained popularity, crossing from Asian communities to mainstream markets, in many western countries. However, less attention has been paid to the safety of these foods. In South-East Asia, fermented products are still produced following traditional methods. Therefore, consumers are not confident in their microbial safety. The challenges awaiting fermentation in South-East Asia are thus to improve safety and quality in a sustainable system producing tasty and typical fermented products. A possible solution could be the use of starter cultures able to increase the safety of food stuffs. Starters could also help to standardize the production process and reduce ripening times. The current review addresses the role of lactic acid bacteria on the microbiological and chemical safety of Asian legume based fermented products. In particular, their role in the reduction of anti nutritional compounds (e.g. phytates) and protein allergenicity is discussed. Moreover, starters can inihibit the development of amino acid-decarboxylating microbes preventing the accumulation of biogenic amines, they can also be useful to reduce the accumulation of mycotoxins and inhibit pathogens' development. Finally, their role in the degradation of pesticides is analyzed. [ABSTRACT FROM AUTHOR]

South-East Asia is well-known for traditionally fermented foods. However, these products are generally still produced at small scale following traditional procedures. Nowadays, consumers are particularly aware of the health concerns regarding food additives; the health benefits of "natural" and "traditional" foods, processed with no added chemical preservatives, are becoming more and more attractive. Therefore, their confidence towards safety and quality of Asian fermented foods is low. Major food safety concerns are related not only to food production methods, but also to how foods are processed, stored, sold and consumed. In this review the main factors affecting food safety are analysed. They are not limited only to the improper use of chemicals such as pesticides or antibiotics, but also to improper processing and handling during storage which could provoke the accumulation of toxic compounds such as mycotoxins or biogenic amines. Urgent attention is required to improve the quality of the ingredients and the integration of food safety management systems for industrial growth. Therefore, in the last part of this review directions to improve the food safety of fermented foods are proposed. • Several safety risks concern South-East Asia fermented food. • Bad agriculture practices are responsible for many contaminations. • The use of a selected flora could decrease many problems. • Many actors of the production chain seem unaware of the risks. • Some products exhibit a high safety quality showing that solutions exist. [ABSTRACT FROM AUTHOR]