This study aimed to acquire a low-cost medium to produce high-yields of lipases from Burkholderia sp. Bps1 by using a statistic method so as to optimize the compositions of medium in the following two steps: 1) a single factor experiment (SFE) was conducted to screen the most significant factors affecting lipase activity to determine the optimal carbon source (molasses), nitrogen source (peptone) and inducer (palm oil); 2) a central composite design (CCD) and response surface methodology (RSM) were used to further optimize the previously mentioned factors to acquire an optimal combination consisting of 9.7 g/L molasses, 13.7 g/L peptone and 0.60% (v/v) palm oil. The optimized lipases activity reached 153.537 U/mL which was 30 times greater than the activity of the primary enzyme. This research used a statistical method to improve the production of lipases from submerged fermentation and formed a theoretical foundation for the industrial production of lipases using low cost raw materials.
The kinetics of hardness changes in soybeans and red kidney beans during cooking were analyzed in presoaked and unsoaked samples. Unsoaked test samples were heated to 10–99.5 °C, and changes in water absorption and hardness were measured. These rates were compared to those of control samples that had been presoaked before cooking. Based on the slope of the line from the first-order plot, softening of dry legumes to reach the optimum edible state occurred through reactions that included “softening due to water absorption” and “softening due to heating”. A two-step reaction was also involved in the “softening due to heating” of soybeans and red kidney beans after reaching hardness of 30 N, which was the lower limit of “softening due to water absorption”. Furthermore, we predicted the precise cooking time with temperature changes by determining the softening rate constants at an arbitrary temperature from the Arrhenius equation.
The enhanced β-glucosidase of Lactobacillus plantarum BCRC 10357 was investigated by a strategic ultrasound treatment on bacteria at different growth stages to induce biological stress response for biotransformation of isoflavones from glucosides to aglycones in okara. Without ultrasound, the highest β-glucosidase activity was occurred in 12-h incubation as 24.45 U/mL; while after ultrasound treatment at death phase, the highest β-glucosidase activity was greatly enhanced to 48.80 U/mL in 24-h re-incubation, showing the bacteria at early death phase behaving the highest resistance to stress than at other stages. With strategically ultrasound-treated L. plantarum BCRC 10357 to ferment okara in the broth at 37 °C, the fraction of bioactive aglycones (daidzein and genistein) in isoflavones was increased from 57% in 12 h to 89% in 36 h. The effective method to improve β-glucosidase released from L. plantarum was developed for the valorization of okara as potential functional ingredients in food.
Coeliac disease has recently attracted interest in food science research. In search of gluten-free (GF) bread with good quality and nutritional value, several sources have been used in the formulation of GF composite flours. The goal of the present work was to study the textural and physical properties as well as the nutritional and sensory characteristics of GF Danish bread made with composite flour based on a mixture of flours and starches. First, we identified the optimal GF formulation by experimental orthogonal design. Regarding bread quality, optimisation of the doughs positively affected the textural and physical parameters of the bread. Moreover, some nutritional values were improved by increasing the ash and slowly digestible starch, and these breads had higher total phenol content and antioxidant capacity. In sensory analysis, the optimized breads received higher scores for flavour, aroma and overall acceptance attributes from the panellists.
The structure of fine starch prepared via a compressed hot water process at different temperatures (160–180 °C) was analyzed using dynamic light scattering and size-exclusion chromatography with multi-angle light scattering and differential refractive index detection. Changes in the molecular weight, polydispersity, hydrodynamic radius, and radius of gyration were assessed. The intrinsic viscosity of the fine starch solution was derived from the Flory-Fox and Ptitsyn-Eizner equations. The weight-averaged molecular weight decreased to 7.29×105 g/mol, and the average hydrodynamic radius and weight-averaged radius of gyration decreased by 34.9 nm and 14.6 nm, respectively, at 180 °C. In fine starch prepared at 160 °C, 165 °C, and 170 °C, tails in the multi-angle light scattering peaks, upswings in the conformation plots, and upturns in the plots of gyration radii and elution volumes were all the result of branching structures. At 175 °C and 180 °C, amylopectin branching was diminished and symmetric scattering peaks were observed. We propose a pathway for waxy rice starch hydrolysis by a compressed hot water process.
Accidental and/or incidental adulterations of foods by porcine ingredients are common in the globalized food processing industry. Food mislabelling and fraudulent substitutions of non-porcine ingredients with porcine ones are objectionable to those who abstain from porcine derived products due to habitual (e.g., vegans and vegetarians), medical (e.g., porcine allergies), legal (fraudulent labelling), economic (e.g., substitution of expensive meat with cheaper pork meat) and cultural or religious grounds (e.g., Islamic and Jewish dietary restrictions). Thus, a strong demand exists for a fast and sensitive method for quantitative sensing of porcine DNA in food. In this study, we are reporting the development of probe-free real-time PCR assay with new primer sets targeting the cytochrome b gene for the fast and sensitive detection of porcine DNA in real food samples. Standard curve was developed with six ten-fold dilutions of the DNA standard and the assay successfully detected up to 0.00001 ng/µL of porcine DNA and as low as 0.001% porcine adulteration in raw pork-chicken binary mixture. The standard curve indicated a linear regression of R2 value of 0.990 and an efficiency of 92.5%. The Ct value range for the detected pork DNA from the 35 food samples tested was 16.03–28.76. We confirmed the assay's specificity to porcine DNA against nine non-porcine animal species and 6 vegetables species.
In the present work mass and energy transfer during microwave dehydration of vegetables were studied. Microwaves interact with the polar molecules of food enabling its heating and dehydration. This interaction is affected by the change of food properties due to temperature increase and water content reduction. In certain products, the dependence of dielectric properties with temperature is affected by a change in the food structure as a consequence of the chemical change of certain components and of the water loss. Lambert's law, that considers an exponential decay of incident microwave power, was applied to model these interactions. Additionally, two consecutive stages must be considered: initial heating, followed by intensive evaporation at constant temperature. The model was successfully validated for data published in literature related to slabs of microwave dehydrated potatoes and carrots, considering different processing times, power densities, pressure and sample size.
The aim of the current study was to reduce the fat content of salad dressings using microparticulated egg white proteins (MEWP) as fat mimetic. In this regard, the effects of heating and shearing conditions on textural properties, rheological properties, and color parameters of MEWP were investigated. Statistical analysis with uniform design methodology showed that there was a significant correlation between investigated responses and process variables (P ≤ 0.05) except for rotational speed. Based on the optimal conditions (13 min for heat time, 3.6 for solution pH value, 90 g/L for protein addition amount, 60 s for shear time, 10000 r/min for rotational speed) produced by the optimization of process conditions, the textural and sensory properties, rheological properties, and color of MEWP were comparable to the commercial salad dressing (CSD). The results indicated that MEWP can be used as fat mimetic for the production of low-fat salad dressings.
While the quality and safety of rice, which is Cambodia's staple food, are recently attracting attention, the actual situation in Cambodia has not been researched or surveyed. In this work, 72 samples comprising 4 rice varieties, Neang Minh, Phka Khnei, Somali and Phka Rumduol, were collected from 3 shops in each of 6 local open markets of Phnom Penh and were analyzed. As physical measurements, grain moisture, grain weight and grain dimension were measured, and a grain scanner was used to measure: (1) whole and broken grains; (2) chalky, red and damaged grains; (3) level of accepted/defected grains; (4) level of mature grains; (5) glutinous grains; and (6) water-soaked cracked grains. In terms of biological measurements, the number of insects and the number and identification of bacteria and fungi were analyzed. The results showed that by variety, Somali and Phka Rumduol were generally higher in quality than Neang Minh and Phka Khnei. With respect to markets, some lacked good storage and selling conditions for some rice varieties. This market survey in Cambodia revealed that serious technical problems and challenges regarding quality and safety remain.
Elasticity index (EI), quality during storage, and shelf-life (SL) were assessed in 16 cultivars of tree-ripe mango fruit. All fruits were individually wrapped in polyethylene film and stored for 10 days at 25 °C. EI rapidly declined over the first 2 days of storage regardless of the cultivar, after which the decline was more gradual. EI reduction rate (EIRR) from day 2 to day 10 of storage was lowest (7% and 9%) in ‘Irwin’ and ‘Glenn’, followed by ‘Khieo Sawoei’. After 10 days, the EI for these cultivars was 57–79 × 105 ƒ22·m2/3 (ƒ2, second resonance frequency; m, fresh weight of a fruit). In contrast, EIRRs for ‘Dot’ and ‘Valencia Pride’ cultivars were 66% and 59%, respectively, and that of ‘Amataiko’ was 48%; EI after 10 days of storage for these cultivars was 23–30 × 105 ƒ22·m2/3. EIRRs of the other 10 cultivars were between 23% and 41%. Weight loss after 10 days of storage was highest in ‘Dot’ and ‘Amataiko’ (4.6% and 3.6%), but lower in the other cultivars (1.4% to 2.4%). The degree of water-soaked symptoms (WSS, translucent flesh tissue) was greatest in ‘Alphonso’, followed by ‘Valencia Pride’, ‘Dot’, ‘Spirit of '76’, ‘Nam Doc Mai’, ‘Golden Lippens’, and ‘Aikou’. In contrast, no WSS were observed in ‘Irwin’, while ‘Beni Keitt’, ‘Edward’ and ‘Glenn’ showed few symptoms, and ‘Amataiko’ showed slightly more WSS. SL score of each fruit was calculated by adding the score obtained by EI (0 to 3) to a score based on the degree of WSS after 10 days of storage (also 0 to 3). SLs (SL of more than 10 days under room temperature can be estimated) were good for ‘Irwin’, ‘Glenn’, ‘Edward’, and ‘Khieo Sawoei’; moderate (SL of 8–10 days) for ‘Beni Keitt’, ‘Sensation’, ‘Florigon’, and ‘Tommy Atkins’; poor (SL of 4–5 days) for ‘Amataiko’, ‘Aikou’, ‘Nam Doc Mai’, ‘Golden Lippens’, and ‘Spirit of '76’; and very poor (SL of 2–3 days) for ‘Alphonso’, ‘Valencia Pride’, and ‘Dot’. These results clearly revealed cultivar differences in EIRRs, WSS and SLs of ripe mangoes, and suggested the possibility of estimating SL based on EI and the degree of WSS after storage.
Heat moisture treatment (HMT) is a processing method used to improve the physicochemical properties of starch. Here, to inform technology with respect to increasing resistant starch (RS) in rice, three rice flours with different starch structures—namely, Koshihikari, Koshinokaori, and Goami2 (GA2)—were treated at 120 °C and 14%–26% humidity and compared with cornstarch. HMT increased the RS content of all specimens, with GA2 showing a marked RS increase up to 11.0%. HMT also increased the gelatinization temperature (Tgel) of all samples, as shown by differential scanning calorimetry, and RS content tended to increase with increasing Tgel values. As shown by the increase in relative crystallinity by X-ray diffraction and change in the iodine absorption spectrum, HMT easily changed the starch structure in GA2, leading to increased RS. These results support GA2 as a suitable rice cultivar for bio-functional rice products such as low glycemic index foods.
Lactic acid (LA) has been used for wide range of food processing and industrial applications, for example, as a raw material of biodegradable plastics, poly(lactic acid)s (PLAs). Thus, there is a demand to incorporate acid-resistance for effective LA production. Acid-tolerant lactic acid bacteria (LAB), Lactobacillus acetotolerans HT, has been isolated from rice vinegar (pH 2.9, 6% acetic acid). In this study, genes for the D- and L-lactate dehydrogenases (D-LDH, L-LDH1, and L-LDH2) of Lb. acetotolerans HT, which constitute the key enzymes in cell growth and lactic acid production, were cloned and identified. Through heterologous expression of LDH genes in Escherichia coli DH5α, recombinant E. coli DH5α harboring the D-LDH (ldhD) or L-LDH1 (ldhL1) genes were found to produce D-LA or L-LA, respectively, whereas the strain harboring the L-LDH2 (ldhL2) gene did not produce L-LA. This finding strongly suggests that the translational product of the ldhL2 gene does not exhibit L-LDH activity in vivo.
While many studies have examined the binding of phytate to proteins and/or minerals, little information is available on the number of complex types and combinations of binding molecules. In this study, interactions of phytate with proteins and divalent ions in the soluble fraction of soymilk obtained from the soybean cultivar Tachinagaha were examined using a Sephacryl S-400 HR column. Phosphorus and divalent ions were detected using inductively coupled plasma atomic emission spectroscopy. Phytate was identified as the phosphorus peak digested by phytase. Three phytate peaks were detected in fractions 21, 49, and 53. The phytate in fraction 21, indicating the presence of the largest complex, was co-eluted with proteins and disappeared after proteinase K treatment. The phytate in fraction 49 was co-eluted with iron, while that in fraction 53 was co-eluted with calcium. Our methods have potential applicability for detecting mineral-phytate and protein-phytate interactions.
The present study was conducted to determine the effect of oral administration of phytosterol esters (PS, 308 mg/kg·d), tea extracts (TE, 300 mg/kg·d) and their combination on serum, liver and fecal lipids of SD rats induced by high-cholesterol diets. After 12 weeks, animals were sacrificed and followed immediately with the collection of blood and organ samples. Results showed that PS and TE alone retained its own lipid-lowering profiles. The combination of PS and TE decreased both serum cholesterol and triglyceride levels, and produced an additive effect on serum LDL-C level reduction. Most importantly was that PS+TE produced a complementary effect in suppressing body weight and fat mass, promoting fecal lipid excretion and reducing liver weight and liver lipids, suggesting the combination was more effective than either PS or TE alone. These results demonstrated that PS+TE could effectively prevent the formation of obesity, single and mixed hyperlipidemia without the observation of any toxic effect. Therefore, PS+TE could be considered as a potential nutraceutical or functional ingredient to prevent cardiovascular diseases and its related complications.
A metabolic analysis technique employing gas chromatography-mass spectrometry was used to distinguish between muscle tissue types in yellowtail Seriola quinqueradiata. The dataset of metabolites from each yellowtail muscle type was subjected to metabolic profile analysis using the SIMCA 14 software package. Orthogonal partial least squares discriminant analysis revealed a marked difference in metabolic profiles of ordinary muscle (OM) and dark muscle (DM), and OM types were further separated into three groups (dorsal, caudal and ventral). Further, several metabolites, such as ornithine for OM vs DM and glycerol-3-phosphate for OM tissue types were identified as potential markers for distinguishing types of yellowtail flesh by S-plot analysis. Based on these findings, metabolic analysis techniques could become useful tools for distinguishing among fish muscle types.
Chicken gizzard inner lining (GIL) is a by-product of animal meat products. This study examines the chemical characteristics and functional proteins of GIL. Our results demonstrate that GIL is protein-rich and contains essential amino acids for humans. In addition, we analyzed soluble GIL proteins in GIL and categorized the identified proteins into 12 functional groups or processes. Moreover, biochemical analysis revealed that the 18-kDa antrum mucosa protein (Gastrokine-1 protein, GKN-1), which is known to support gastroprotective and physiological activities, was the most abundant protein of GIL. In conclusion, GIL is an important source of proteins and bioactive compounds, such as GKN-1. Therefore, GIL may have some capabilities as important applications in food processing.
The aim of the study was to investigate the combinational effect of Pine needle polysaccharide (PNP) and Kudzu flavonoids (KF) on cell differentiation and fat metabolism in 3T3-L1 cells. 3T3-L1 cells were treated with various concentrations of PNP or/and KF. Cell viability, Oil red O staining, intracellular TG, glycerol in culture medium, levels of cytokines and expression of transcription factors genes were evaluated. PNP and KF combination significantly suppressed cells differentiation and fat accumulation by inhibiting the mRNA expression of PPARγ2 (peroxisome proliferator activated receptor-γ2), C/EBPα (CCAAT/enhancer binding proteins-α) and SREBP-1c (sterol regulatory element binding protein-1c) in 3T3-L1 cells. In addition, the gene expression and secretion of leptin and IL-6 were inhibited, adiponectin was significantly increased, secretion of TNF-α was inhibited by PNP and KF combination. Taken together, PNP and KF combination may exert anti-adipogenic effects through regulation of lipid metabolism gene expression of the transcription factors and cytokines. The findings suggested that PNP and KF combination may be explored as a potentially promising food additive for prevention of obesity.
Outbreaks of foodborne illness caused by Listeria monocytogenes in or on fresh produce have been reported. Several contamination routes have been proposed and the cultivation process is one of the suspected routes. Leaf lettuce is one of the most important fresh produce products. In the present paper, we investigated the possible routes of L. monocytogenes contamination in leaf lettuce during cultivation. Leaf lettuce was cultivated in soils inoculated with cocktails of three isolates of L. monocytogenes belonging to different serotypes (1/2a, 1/2b, and 4b). The viability and injury state of L. monocytogenes in soils, and bacteria survival in or on leaf lettuce were investigated during 10 weeks of cultivation. Soils were artificially contaminated with L. monocytogenes at levels of 4, 6 or 8 log CFU/g, followed by cultivation of leaf lettuce in the contaminated soils. Populations of L. monocytogenes in the soil decreased to less than the detection limit (< 2 log CFU/g) at 8–10 weeks after the start of cultivation. L. monocytogenes was detected in some harvested leaf lettuce leaves at low levels, almost equivalent to the detection limit. As L. monocytogenes was not detected in the leaves of leaf lettuce plants cultivated in highly-contaminated soils after surface disinfection, the possibility of internalization of L. monocytogenes into leaf lettuce plants was considered low. Spraying of water contaminated with bacteria at greater than 3.2 log CFU/plant led to the survival of bacteria on the leaf lettuce leaves even after seven days. Furthermore, leaf damage prolonged the survival period of bacteria on the leaves.
Radical scavenging and singlet oxygen quenching activities of 32 kinds of fruits and vegetables typically consumed in Japan were evaluated using both the oxygen radical absorbance capacity (ORAC) and singlet oxygen absorption capacity (SOAC) methods. Total-ORAC and SOAC values correlated with total polyphenol (r = 0.92) and carotenoid (r = 0.85) contents. From the data of daily fruit and vegetable intake (110.0 and 286.4 g, respectively) in the National Health and Nutrition Survey in Japan, daily ORAC and SOAC intakes were estimated to be 3177.7 µmol trolox equivalents/day and 1610.3 µmol α-tocopherol equivalents/day, respectively. The major contributors to ORAC intake were apples, Satsuma mandarins, edible burdock, and onions, accounting for 44.3% of the total; whereas Japanese squash, carrots, tomatoes, and spinach accounted for 73.2% of total SOAC intake. Total antioxidant capacity assessment of foods may facilitate the identification of relationships between antioxidant intake and disease risk reduction.
We investigated the anti-allergic activities of rapeseed cake extract (RCEx) using RBL-2H3 cells. RCEx was produced using the solvent methanol:acetone:water (7:7:6, v/v/v) and was also alkaline-hydrolyzed (AH-RCEx) using HP-20 column and the ethanol stepwise method. AH-RCEx showed a concentration-dependent decrease in degranulation in RBL-2H3 cells, whereas RCEx did not. The water-extracted fraction (WEx) from AH-RCEx mildly inhibited degranulation, and the 40% and 60% ethanol-eluted (EtEx) fractions of AH-RCEx significantly inhibited degranulation compared with that in the control. In HPLC and TLC, the main peak of WEx was consistent with sinapinic acid (SA). In addition, we found a characteristic m/z 473.15 peak in the 40% and 60% EtEx, which was not SA. Therefore, it was suggested that the anti-allergic constituents in rapeseed cake were successfully extracted by alkaline hydrolysis, and their activities were attributed to SA and other unknown compounds.
Tyrosol (2-(4-hydroxyphenyl) ethanol) is a phenylethanoid present in olive oil, with anti-oxidative, anti-inflammatory, and cerebroneural protection effects. In this study, the protective effect of tyrosol against oxidative damage was measured in L6 muscle cells. Tyrosol effectively inhibited H2O2-induced L6 cell death in part through regulation of ERK, JNK, and p38 MAP kinase and increased ATP production. In addition, it increased HO-1 expression in the cell. Based on results, tyrosol is effective in inhibiting oxidative damage of muscle cells.