Encapsulation of probiotic Lactobacillus acidophilus by ionic gelation with electrostatic extrusion for enhancement of survival under simulated gastric conditions and during refrigerated storage

The probiotic Lactobacillus acidophilus was encapsulated in biodegradable and biocompatible capsules prepared by ionic gelation between phytic acid (PA) and chitosan (CS) with an electrostatic extrusion method. Calcium carbonate (CaCO₃) and starch were used as co‐encapsulants for improvement of capsule stability. Capsules were characterised and evaluated for survival of encapsulated L. acidophilus cells in simulated gastric fluid (SGF) and during refrigerated storage. Loading capacity values of PA‐CS capsules, PA‐CS‐starch capsules and PA‐CS‐CaCO₃ capsules were 8.20, 8.12 and 7.81 log CFU g^?1 of wet capsule, respectively. Capsules showed particle sizes of 1.3–1.5 mm and a uniform spherical shape. PA‐CS‐CaCO₃ capsules were the most stable vehicles for the protection of probiotic cells against acidic damage, particularly at pH 1.5 and pH 2. L. acidophilus cells from PA‐CS‐CaCO₃ capsules showed only a 0.64 log CFU reduction in numbers after 2 h in pH 1.5 SGF conditions. The numbers of L. acidophilus encapsulated in PA‐CS‐CaCO₃ capsules were decreased by only 0.69 log CFU g^?1, while PA‐CS capsules and PA‐CS‐starch capsule numbers were reduced by more than 1.45 log CFU g^?1 after 4 weeks at 4 °C. Addition of calcium carbonate to PA‐CS capsules provided protection against acid injury via antacid and buffering effects for encapsulation of L. acidophilus.     

Addition of seaweed (Laminaria digitata) extracts containing laminarin and fucoidan to porcine diets: Influence on the quality and shelf-life of fresh pork

A seaweed extract containing laminarin (L) and fucoidan (F) (L/F) was manufactured from brown seaweed (Laminaria digitata) in spray-dried (L/F-SD) and wet (L/F-WS) forms. The effect of supplementation of pig diets with L/F-SD and L/F-WS (L, 500 mg/kg feed; F, 420 mg/kg feed) for 21 days pre-slaughter, on quality indices of fresh M. longissimus dorsi (LD) steaks was examined. Susceptibility of porcine liver, heart, kidney and lung tissue homogenates to iron-induced (1 mM FeSO₄) lipid oxidation was also investigated. Dietary supplementation with L/F did not increase plasma total antioxidant status (TAS). In LD steaks stored in modified atmosphere packs (80% O₂:20% CO₂) (MAP) for up to 15 days at 4 °C, muscle pH, surface colour (CIE ‘L*’ lightness, ‘a*’ redness and ‘b*’ yellowness values) and microbiology (psychrotrophic and mesophilic counts, log CFU/g pork) were unaffected by dietary L/F. In general, levels of lipid oxidation (TBARS, mg MDA (malondialdehyde)/kg pork) followed the order: C > LF-SD > L/F-WS. A statistically significant reduction in lipid oxidation (P < 0.05) was observed in LD steaks from 75% of pigs (n = 6) fed with L/F-WS compared to controls. Iron-induced lipid oxidation increased in liver, heart, kidney and lung tissue homogenates over the 24 h storage period and dietary L/F-WS reduced lipid oxidation to the greatest extent in liver tissue homogenates. Results demonstrate potential for the incorporation of marine-derived bioactive antioxidant components into muscle foods via the animal's diet.     

Investigation of TiO2 nanoparticle efficiency on decolourisation of industrial date syrup

The TiO₂ nanoparticle photocatalyst was used to decolourise industrial date syrup. The effect of TiO₂ concentration (1 and 4% w/v), UV power (15 and 30 w) and processing time (12 and 48 h) on date syrup characteristics was investigated using a factorial design. The colour, turbidity, sugar content, total phenolic compounds, ash content and mineral (K, Na, Ca, Mg and Fe) of date syrup were analysed. The results demonstrated that using TiO₂ nanoparticle as a photocatalyst for the decolourisation of date syrup is an effective and promising method. Colour in all treatments was significantly (P < 0.05) reduced between 30 and 53% in comparison with the initial date syrup (491 000 IU), and the reduction was even higher for date syrup turbidity (between 47 and 75%). The result showed that the process condition significantly affected the colour and turbidity reduction. On the basis of the result, the best treatment was TiO₂ 4%, 15 w and 48 h. Under this condition, date syrup colour, turbidity, ash content, sugar content reduced by 52%, 61%, 13% and 9%, respectively.     

Rheological properties of sodium alginate in an aqueous system during gelation in relation to supermolecular structures and Ca binding

Gelation behavior of sodium alginate was investigated in an aqueous system at various CaCO₃ doses using two alginate samples of different mannuronate (M)/guluronate (G) ratios but with comparable molecular masses. Macroscopic rheological properties of the polysaccharide were discussed during gelation in relation to microscopic supermolecular structures imaged by atomic force microscopy and Ca²⁺ binding. At fixed concentrations of the polysaccharide (0.5 w/v%) and glucono-δ-lactone (15 mM) as an acidic material, the G-rich sample was higher in elasticity with rod-like molecular assemblies at the highest CaCO₃ dose; 15 mM, while the M-rich sample was higher in elasticity with network-like molecular assemblies at the lowest CaCO₃ dose; 3.75 mM. Gelation behavior near the sol-to-gel transition was generally described by the percolation model, except for the M-rich sample at the lowest CaCO₃ dose. A critical CaCO₃ dose corresponded to 7.5 mM at which both alginate samples showed essentially the same gelation kinetics. In an equilibrium state, it was estimated that the G-rich sample was bound to larger amount of Ca²⁺ at the lowest CaCO₃ dose, while the M-rich sample was bound to larger amount of Ca²⁺ at the highest CaCO₃ dose. The amount of bound Ca²⁺ did not directly relate to elasticity of the system. Based on these results, dominant block structures are suggested for gelation.     

Rapid lactate oxidase‐based assay for lactate content in milk to ascertain its hygienic quality

A rapid method for qualitative and quantitative assaying of l ‐lactate in milk is described. The method is based on oxidation of lactate by lactate oxidase with the simultaneous formation of H₂O₂ which subsequently oxidises 2, 4, 6‐tribromo 3‐hydroxy benzoic acid (TBHBA) in the presence of peroxidase. Oxidised TBHBA then reacts with 4‐amino antipyrine to obtain magenta colour (λ_max = 523 nm). In the qualitative assay, colour change becomes visible in raw milk samples spiked with 300 mg lactate/L. The absorbance increases linearly up to 1000 mg/L. The method can be used for rapid assessment of the hygienic quality of milk.     

Assessment of nanoparticle paprika oleoresin on marinating performance and sensory acceptance of poultry meat

The effects of nanoparticle paprika oleoresin (1 and 3 g/100 mL) and carrier system (water/milk) on the physical and sensory properties of cooked marinated chicken were investigated. Marinade absorption, cooking loss, surface colour (L1, a1, b1 values), penetration force, moisture and fat content were measured. Sensory properties, including; surface colour (orange, red), colour penetration, aroma, toughness, juiciness, flavour acceptability, paprika flavour, saltiness, hotness and overall acceptability were also evaluated using 25 naïve assessors (consumers). 3 g/100 mL paprika produced greater surface CIE a1 (redness) and b1 (yellowness), sensory surface orange, red and colour penetration attributes. The carrier 0/100 (water to milk ratio) with nanoparticle paprika oleoresin was shown to increase the colour quality of cooked marinated chicken by increasing (P < 0.05) surface CIE a1 (redness) and b1 (yellowness) value, whereas the 100/0 water to milk ratio carrier system provided a better colour penetration. In conclusion the application of nanoparticle paprika successfully enhanced marinating performance.     

Evaluation of iron‐fortified Feta cheese for physicochemical and sensory properties

Standardised cow's milk (fat 3 g/100 g) was used to manufacture Feta cheese fortified with 40, 60 and 80 mg of iron/kg cheese using ferrous sulphate (FeSO₄), ferric chloride (FeCl₃), ferric pyrophosphate (Fe₄ (P₂O₇)₃) and microencapsulated ferrous sulphate. Chemical composition and sensory characteristics of fortified cheeses were determined after 60 days of ripening, during which the iron content and thiobarbituric acid (TBA) values were measured. The metallic taste, colour, flavour, overall score and TBA values were statistically (P < 0.05) affected by the source and concentration of iron. The best quality was found in cheeses fortified with 40 mg/kg of microencapsulated ferrous sulphate.     

Bacterial inactivation and quality changes in fresh-cut avocado treated with intense light pulses

This study investigated the impact of intense light pulses (ILP) on inactivation of Listeria innocua and Escherichia coli as well as quality changes in fresh-cut avocado. Cylinders of avocado inoculated with L. innocua or E. coli were placed in plastic trays, which were sealed with a 64-μm-thick polypropylene film (oxygen permeability of 110 cm³ O₂ m⁻² bar⁻¹ day⁻¹ at 23 °C and 0% RH) and subjected to 15 or 30 pulses at fluencies of 0.4 J/cm² per pulse and then stored for 15 days at 5 °C. In addition to L. innocua and E. coli counts, the headspace atmosphere, pH, colour and firmness were measured. The growth of E. coli and L. innocua was more effectively inhibited when increasing treatment intensity. Hence, significant inactivation was obtained in samples treated with 15 and 30 pulses for L. innocua (2.61 and 2.97 log CFU/g, respectively) and E. coli (2.90 and 3.33 log CFU/g, respectively) just after processing. Oxygen concentrations were significantly reduced, whereas CO₂ and ethanol concentrations increased due to product respiration; however, ethylene production was decreased by the effect of ILP treatments. The use of 30 pulses affected the colour and firmness of fresh-cut avocado, causing browning and softening.     

Enhancement of the phytochemical and fibre content of beef patties with Himanthalia elongata seaweed

The effect of adding Himanthalia elongata seaweed (10–40% w/w) as a source of antioxidants and dietary fibre on physical, chemical, microbial and sensory traits of cooked beef patties was studied throughout chilled storage. Patties with seaweed showed reduced cooking losses and were nearly 50% more tender as compared to patties without seaweed. Microbiological counts and lipid oxidation were significantly lower in patties containing seaweed (P < 0.05), and by day 30 of storage, there was no bacterial growth in samples with ≥20% seaweed and lipid oxidation levels were low (0.61 mg malondialdehyde kg^?1 of sample). Seaweed incorporation significantly increased the dietary fibre (1.64 g per 100 g fw in 40% seaweed patties), total phenolic content (up to 28.11 mg GAE per 100 g fw) and DPPH radical scavenging activity (up to 52.32%) of patties compared to the control. Sensory analysis indicated that the seaweed patties were accepted by consumers in terms of aroma, appearance, texture and taste. Patties containing 40% seaweed were rated highest in terms of overall acceptability, most likely due to improvement in texture and mouthfeel. Addition of seaweed in the formulation of beef patties leads to the enhancement of the nutritional and technological quality together with an acceptable sensory quality.     

Immobilization of endo-inulinase on poly-d-lysine coated CaCO3 micro-particles

Inulinase is widely applied to produce high fructose syrup (HFS) which is used in the food and pharmaceutical industries. Numbers of different techniques such as physical adsorption, entrapment, ion exchange and covalent bonding have been used to immobilize enzymes on solid supports. In this study, an efficient technique for inulinase immobilization was developed which consists of adsorbing a cationic polyelectrolyte poly-d-lysine (PDL) on negatively charged calcium carbonate micro-particles (CaCO₃-MPLs) and immobilizing inulinase through electrostatic interactions between negatively charged amino acids of inulinase and positively charged [CaCO₃/PDL-MPLs] complex. The most effective CaCO₃-MPLs which had the smallest diameter were manufactured using ultrasonic spray pyrolysis; a new application of this method to manufacture the enzyme support. This method enabled us to reduce the particle size to 2.9 μm which showed the highest average protein loading capacity of 21.3 ± 0.1 mg or 32.0 ± 1.3 U enzyme per gram of CaCO₃-MPLs. Two sets of binding sites are available on the [CaCO₃/PDL-MPLs] for inulinase, both resulted in positive cooperation with Hill coefficients of 2.3 and 6.8 for the first and second sets of binding sites, respectively. For the immobilized enzyme, the optimum temperature of activity increased from 50 to 55 °C and immobilization resulted in higher thermal stability. Storage stability of immobilized inulinase increased more than two-fold as demonstrated by half-lives (t_1/2) which increased from 65.2 to 148 days for the free and immobilized inulinases, respectively.     

Addition of seaweed (Laminaria digitata) extracts containing laminarin and fucoidan to porcine diets: Influence on the quality and shelf-life of fresh pork

A seaweed extract containing laminarin (L) and fucoidan (F) (L/F) was manufactured from brown seaweed (Laminaria digitata) in spray-dried (L/F-SD) and wet (L/F-WS) forms. The effect of supplementation of pig diets with L/F-SD and L/F-WS (L, 500 mg/kg feed; F, 420 mg/kg feed) for 21 days pre-slaughter, on quality indices of fresh M. longissimus dorsi (LD) steaks was examined. Susceptibility of porcine liver, heart, kidney and lung tissue homogenates to iron-induced (1 mM FeSO₄) lipid oxidation was also investigated. Dietary supplementation with L/F did not increase plasma total antioxidant status (TAS). In LD steaks stored in modified atmosphere packs (80% O₂:20% CO₂) (MAP) for up to 15 days at 4 °C, muscle pH, surface colour (CIE ‘L*’ lightness, ‘a*’ redness and ‘b*’ yellowness values) and microbiology (psychrotrophic and mesophilic counts, log CFU/g pork) were unaffected by dietary L/F. In general, levels of lipid oxidation (TBARS, mg MDA (malondialdehyde)/kg pork) followed the order: C > LF-SD > L/F-WS. A statistically significant reduction in lipid oxidation (P < 0.05) was observed in LD steaks from 75% of pigs (n = 6) fed with L/F-WS compared to controls. Iron-induced lipid oxidation increased in liver, heart, kidney and lung tissue homogenates over the 24 h storage period and dietary L/F-WS reduced lipid oxidation to the greatest extent in liver tissue homogenates. Results demonstrate potential for the incorporation of marine-derived bioactive antioxidant components into muscle foods via the animal's diet.     

Short- and long-term effects of micro-oxygenation treatments on the colour and phenolic composition of a Cabernet Sauvignon wine aged in barrels and/or bottles

Micro-oxygenation is the controlled and continuous addition of small doses of oxygen to the wine in order to achieve a rational management of the evolution of the colour and mouthfeel properties of red wines. The short and, especially, the long-term effects of this technology on the colour characteristics of wines are still little known. In this study, a Cabernet Sauvignon wine was subjected to oxygenation treatments before (15 mg O₂/L in 3 weeks) and after (6 mg O₂/L in 3 months) malolactic fermentation and then aged for 20 months in barrels and/or bottles. Analysis was carried out of the dissolved oxygen concentration, the acetaldehyde content, and the evolution of several parameters related to the anthocyanic composition and the chromatic characteristics of wines for 113 weeks. The supplying oxygen significantly accelerated the kinetics of the degradation and transformation reactions of anthocyanins providing wines with a more intense bisulphite non-bleachable colour, with little or not impact on the normal evolution of their tonality. These beneficial effects produced during the treatments were kept over time, in such a way that the differences between the micro-oxygenated wines and the control wines remained after 20 months of ageing.     

Optimization of Chitosanase Production by <Emphasis Type="Italic">Trichoderma koningii</Emphasis> sp. Under Solid-State Fermentation

This study aimed at the optimization of the production of chitosanase in solid culture. Trichoderma koningii sp., an entomopathogenic fungus, was used to produce chitosanase under solid-state fermentation using a mixture of wheat bran and chitosan. The incubation period; addition of moistening water and culture medium composition were optimized. The protocol to extract the enzyme was also optimized. The optimal conditions for chitosanase production by T. koningii were obtained using a mixture of 3.0 g of wheat bran and 1.5 g of chitosan, with the addition of 2.5 mL of moistening water (pH 5.5) and of 2.5 mL of saline solution (pH 5.5) containing NaNO₃ (1.0 g/L), (NH₄)₂HPO₄ (1.0 g/L), MgSO₄.7H₂O (1.0 g/L), and NaCl (1.0 g/L). Optimal enzyme extraction was carried out adding 20 mL of sodium acetate buffer (200 mM, pH 5.5) at 30 °C under orbital agitation at 150 rpm for 6 min. The optimized production yielded 4.84 IU/gds.     

Optimization of Trace Metals Concentration on Citric Acid Production by Aspergillus niger NRRL 2001

Citric acid is nowadays produced by submerged fermentation of Aspergillus niger. The process yield depends on the composition of the medium, as well as on the microorganism strain. In this work, the effect of Fe⁺³, Zn⁺², and Mn⁺² on citric acid production by A. niger NRRL 2001 is presented. The culture medium composition was glucose (120 g/L) KH₂PO₄ (1.0 g/L); K₂HPO₄ (1.0 g/L), MgSO₄.7H₂O (0.5 g/L), (NH₄)₂SO₄ (3.0 g/L). The ions Fe⁺³, Zn⁺², and Mn⁺² had their concentrations changed according to an experimental design. The experiments were carried out in an orbital shaker at 200 rpm and 30°C. The strain produced an extracellular polysaccharide that was also quantified. The optimum experimental condition was found using 7.0 mg/L of Fe⁺³ and 6.5 mg/L of Zn⁺² in absence of Mn⁺². No oxalic acid formation was observed using this experimental condition. Metal contents were not significant for the production of the polysaccharide. The highest production rate (2.95 g L⁻¹ day⁻¹) was reached after 10 days of fermentation. After this period, the productivity decreased slightly. In 20 days, the citric acid production rate (2.44 g L⁻¹ day⁻¹) was 82% of the highest productivity. The conversion into citric acid increased continuously, yielding 45.8% in 20 days of fermentation.     

Effect of a brown seaweed (Laminaria digitata) extract containing laminarin and fucoidan on the quality and shelf-life of fresh and cooked minced pork patties

A spray-dried seaweed extract containing laminarin (L, 9.3%) and fucoidan (F, 7.8%) (L/F extract) from brown seaweed (Laminaria digitata) was added directly to minced pork (M. longissimus dorsi) (LD) at levels of 0.01%, 0.1% and 0.5% (w/w). Fresh and cooked minced pork patties were stored in modified atmosphere packs containing 80% O₂:20% CO₂ and 70% N₂:30% CO₂, respectively, for up to 14 days at 4 °C. The L/F extract reduced the surface redness (‘a*’ values) of fresh patties as a function of concentration. The L/F extract (0.5%) exerted the greatest lipid pro-oxidant activity in fresh patties. The L/F extract (0.5%) significantly decreased (P < 0.05) lipid oxidation in cooked patties. The L/F extract had no effect on the microbiological status, pH, water holding capacity (WHC) or cook loss of patties. Pork patties containing 0.01% L/F were preferred by sensory panellists. Further research will focus on the use of refined purified seaweed extracts in functional meat products.     

Comparison of the murine norovirus-1 inactivation in cabbage Kimchi with two different salinities during storage

Enteric noroviruses are occasionally detected in Kimchi, which is a traditional dish made of fermented vegetables. This study was aimed at examining the effects of two levels of salt concentrations on the survival of murine norovirus-1 (MNV-1), a human norovirus surrogate, in experimentally contaminated cabbage Kimchi stored at 5 °C for 10 weeks. The number of total aerobic bacteria (TAB) and lactic acid bacteria (LAB), MNV-1 titer pH, and acidity were measured every week. The titers of MNV-1 in both low (1.17%) and normal (2.22%) salinity cabbage Kimchi were significantly (P < 0.05) decreased with increase in storage time. The overall reduction was 1.75 log₁₀ plaque-forming unit (PFU)/mL in normal salinity cabbage Kimchi and 1.24 log₁₀ PFU/mL in low salinity cabbage Kimchi. The time required to reduce the titer by > 1 log₁₀ PFU/mL in normal and low salinity cabbage Kimchi were 4 and 8 weeks, respectively. The pH value under both salinities significantly (P < 0.05) decreased until 4 weeks. The maximum acidity was 0.83% and 0.79% in normal and low salinity cabbage Kimchi, respectively, during the 10 weeks. The population of TAB and LAB reached up to 7.33 log₁₀ colony-forming unit (CFU)/g as a maximum population during the storage period of 3 weeks in normal salinity cabbage Kimchi. However, the population of TAB and LAB in low salinity cabbage Kimchi reached to 6.99 and 7.04 log₁₀ CFU/g at 5 and 4 weeks, respectively. Through these findings, fermentation factors such as TAB, LAB, pH, and acidity of cabbage Kimchi were influenced by salt concentration. The inactivation of MNV-1 in normal salinity cabbage Kimchi was much faster than that in low salinity cabbage Kimchi because the fermentation in normal salinity cabbage Kimchi progressed more quickly than that in low salinity cabbage Kimchi. However, both salinity cabbage Kimchi were able to infect cells for 70 days even though the MNV-1 was reduced over 1 log₁₀ during fermentation. Therefore, the way to protect cabbage Kimchi from norovirus must be considered.     

Shelf life extension of ground chicken meat using an oxygen absorber and a citrus extract

In the present study the combined effect of an O₂ absorber and a citrus extract (0.1 and 0.2 ml/100 g), on shelf life extension of fresh ground chicken stored at 4 °C was investigated. Microbiological changes [Total viable count (TVC), Pseudomonads, Lactic acid bacteria (LAB), Enterobacteriaceae, and Clostridium spp.)], physicochemical changes (pH, total volatile nitrogen (TVB-N), and colour) and sensory changes (colour, odour and taste) were monitored as a function of treatment and storage time (14 days). Aerobically packaged ground chicken meat stored at 4 °C was taken as the control sample. On day 6 of storage TVC was reduced by 0.5, 1.0 and 1.5 log cfu/g by the citrus extract (0.2 ml/100 g), the O₂ absorber and the combination of the O₂ absorber plus citrus extract (0.2 ml/100 g), respectively (p < 0.05). Initial pH (6.38) showed an increase (6.73) or decrease (5.83) depending on specific treatment. TVB-N ranged between 42.5 and 57.5 mg/kg at the time of sensory rejection. Colour parameters remained unaffected in samples containing the O₂ absorber and/or citrus extract. A 4–5 days product shelf life extension using the combination of O₂ absorber and citrus extract (0.1 ml/100 g) as compared to control samples was achieved.     

The interaction of pulsed electric fields and texturizing ‐ antifreezing agents in quality retention of defrosted potato strips

The combination of pulsed electric fields (PEF) and texturizing and antifreeze agents on quality retention of defrosted potato strips were studied. Potato strips (10 mm thickness, 100 g) were placed in different solutions (1% w/v) of CaCl₂, glycerol, trehalose as well as NaCl and sucrose, treated with PEF (0.5 kV cm^?1, 100 pulses, 4 Hz). Then, all the samples were soaked in the same solutions for 10 min. After draining, samples were packed into polypropylene pouches and stored at ?18 °C for 12 h. Samples were thawed out at room temperature (20 °C) in 3 h. Untreated controls and PEF treated control samples were also frozen and thawed in similar conditions. To assess the potato strip quality, the thawed samples were analysed for moisture content, weight loss, firmness and colour attributes. The results indicate that PEF treatment by itself is not a suitable pre‐treatment method for frozen potato strips and should be assisted by CaCl₂ and trehalose treatment to prevent softening after defrosting. Firmness analyses determined that application of PEF alone results in 2.38 N. However, PEF in combination with CaCl₂ and trehalose result in 2.97 N and 2.99 N, respectively, which are both significantly firmer than the samples solely treated with PEF. CaCl₂ and trehalose were effective in not only maintaining the structural integrity of the cells, but also retaining colour attributes. The L* value was found to be higher (P < 0.05) in CaCl₂ and trehalose treated samples (58.95 and 57.21, respectively), as compared to PEF treated samples (53.97) denoting a darker colour. Application of CaCl₂ and trehalsoe in combination with PEF also resulted in significantly less weight loss after thawing.     

Brines added sodium bicarbonate improve liquid retention and sensory attributes of lightly salted Atlantic cod

To meet the demand for low-salt products, the producers in the food industry are encouraged to reduce the sodium content in processed food. This study reports results of fresh and frozen farmed cod (Gadus morhua L.) fillets injected with varying amounts of NaCl solutions (0, 50, 150 and 250 g/L) with or without an additional 25 g/L sodium bicarbonate (NaHCO₃). Results showed improved yield, better liquid retention during storage, improved flavor, texture, and reduced formation of volatile lipid compounds for the samples injected with a combination of NaCl and NaHCO₃ compared with fillets injected with NaCl or NaHCO₃ only. Brine concentrations for optimum yield and liquid retention in both fresh and frozen cod fillets were found to be between 50 and 150 g/L NaCl with the addition of 25 g/L NaHCO₃. It is concluded that very lightly salted cod fillets with a high liquid retention and improved sensory attributes can be produced by treating the fillets with a combination of NaCl and NaHCO₃.     

Optimization of culture medium for yellow pigments production with <Emphasis Type="Italic">Monascus anka</Emphasis> mutant using response surface methodology

In our laboratory, one Monascus anka mutant able to produce high yield of yellow pigments screened by physical and chemical combination mutagenesis was obtained. This study evaluated peptone, NH₄NO₃ and KH₂PO₄ as the most significant variables for Monascus yellow pigment production by this M. anka mutant MYM in submerged fermentation. Response surface methodology (RSM) optimized these nutrient parameters for maximum yellow pigment production (87.24 OD units), which resulted at 10.3 g/L peptone, 11.9 g/L NH₄NO₃ and 4.7 g/L KH₂PO₄ in the medium. According to the fitting equation, through five replication experiments under the optimized conditions, the average yellow pigment production obtained was 88.14 OD units for flask cultivation and 92.45 OD units for 5 L fermenter cultivation. Meanwhile, the citrinin could not be detected by HPLC method.