Quality characteristics of fermented sour fish cake (Nham‐Pla)

Nham‐Pla (fermented sour fish cakes) were made from four kinds of fish, namely, striped catfish and nile tilapia from the fresh water fish and threadfin bream and barracuda from the marine fish. Sensory evaluation tests showed that Nham‐Pla made from the fresh water fish have a higher acceptability score; and score differences between catfish and nile tilapia are insignificant. However, score differences between threadfin bream and barracuda are noticeably large. Chemical analysis and Microbiological analysis have also been performed. Results indicated that the range of pH readings among a variety of samples varied from 4.50 to 5.80, lactic acid contents varied from 0.49 to 1.13% (w/w), moisture contents varied from 75.7 to 80.1% (w/w), protein contents varied from 14.08 to 14.92% (vv/w), fat content varied from 0.49 to 1.95% (w/w) and salt contents varied from 1.61 to 1.97% (w/w). Among the forty bacterial isolates identified, twenty three were identified as Leuconostoc mesenteroides, six as Lactobacillus plantarum, three as Pediococcus damnosus, three as Lactobacillus Ieichmanii, two as Lactobacillus delbmekii, two as Lactobacillus brevis and one as Lactobacillus acidophilus.     

Does the presence of an arteriovenous fistula alter changes in body water following hemodialysis as determined by multifrequency bioelectrical impedance assessment?

Multifrequency bioelectrical impedance assessments (MFBIAs) aid clinical assessment of hydration status for hemodialysis (HD) patients. Many MFBIA devices are restricted to whole body measurements and as many patients dialyze using arteriovenous fistulas (AVFs), we wished to determine whether AVFs affected body water measurements. We reviewed pre‐ and post‐HD segmental MFBIA measurements in 229 patients attending for midweek HD sessions. Up to 144 were dialyzed with a left arm AVF (L‐AVF), 42 with a right arm AVF (R‐AVF), and 43 by central venous access catheter (CVC). Water content and lean tissue were greater in the left compared to right arm in those patients with L‐AVFs both pre and post dialysis (pre 2.1 ± 0.7 vs. 2.0 ± 0.7 L, and post 1.9 ± 0.6 vs. 1.8 ± 0.6 L and pre 2.65 ± 0.9 vs. 2.56 ± 0.8 kg, and post 2.34 ± 0.8 vs. 2.48 ± 0.8 vs. 2.34 ± 0.8 kg, respectively) and were also greater in the right compared to left arm for those patients dialyzing with R‐AVFs (pre‐HD 1.92 ± 0.5 vs. 1.86 ± 0.6 L and post‐HD 1.79 ± 0.5 vs. 1.7 ± 0.5 L, and pre‐HD 2.47 ± 0.6 vs. 2.38 ± 0.7 kg and post‐HD 2.3 ± 0.74 vs. 1.28 ± 0.7 kg, respectively), all Ps < 0.05. There were no significant differences in arm volumes or composition pre or post dialysis in those dialyzing with CVCs. Segmental MFBIA detects differences in arm water and lean mass in patients with AVFs. The presence on an AVF increases the water content in the ipsilateral arm both pre and post HD. This increased water content of the fistula arm will not be detected by whole body bioimpedance devices.     

Partial purification and characterization of trypsin-like proteinases in Indian anchovy (Stolephorus spp.)

Four fractions (P111, P21, P31, and P4) of proteinases were obtained from various purification steps including heat treatment (60 °C, 10 min), 30–60% ammonium sulfate precipitation, anion exchange, hydrophobic interaction, and gel filtration chromatography. Optimal temperature and pH of all fractions were 50–60 °C and 8.5, respectively. All partially purified proteinases preferably hydrolyzed substrates containing Arg at the P₁ position. All proteinases were inhibited by soybean trypsin inhibitor, leupeptin, and N-tosyl-l-lysine chloromethyl ketone. Partially purified proteinases were stable at 35 °C up to 12 h. However, their activity decreased about 40% when incubated at the optimal temperature (50–55 °C) for 2 h. Only P111 was stable at its optimal temperature (60 °C) up to 12 h. Molecular weight (MW) of P111, P21, and P31 was estimated to be 27, 33, 37, 43, 48, 55, 60, and 65 kDa, while MW of P4 was 39 kDa based on activity staining. All partially purified proteinases hydrolyzed washed anchovy mince at 4.0 M NaCl, pH 8.5, at 35 °C and at their optimal temperatures (50–60 °C).     

Acceleration of Thai fish sauce fermentation using proteinases and bacterial starter cultures

ABSTRACT:  A means to accelerate fish sauce fermentation without adversely affecting fish sauce quality was investigated. Starter cultures prepared from Virgibacillus sp. SK33, Virgibacillus sp. SK37, and Staphylococcus sp. SK1-1-5 were added separately to anchovy that was hydrolyzed by 0.25% Alcalase at 60 °C for 2 h followed by 0.5% Flavourzyme at 50 °C for 4 h. The mixtures were then adjusted to contain 25% solar salt and incubated at 35 °C for 4 mo. α-Amino contents of all inoculated samples were higher than the control (without the addition of starter culture) during the course of fermentation. After 4-mo fermentation, the samples inoculated with Staphylococcus sp. SK1-1-5 contained the highest α-amino content of 733.37 ± 13.89 mM while that of the control was 682.67 ± 3.33 mM. Amino acid profiles of inoculated samples showed similar patterns to that of commercial product fermented for 12 mo, with glutamic, aspartic, and lysine being predominant amino acids. Virgibacillus sp. SK33 appeared to decrease histamine content of fish sauce by 50% when compared to the control. Volatile compounds analyzed by GC–MS of all inoculated samples fermented for 4 mo exhibited a similar pattern to those of the 12-mo-old commercial product. Samples inoculated with Staphylococcus sp. SK1-1-5 produced higher levels of volatile fatty acids and showed similar sensory characteristics to the commercial fish sauce fermented for 12 mo. Staphylococcus sp. SK1-1-5 is a potential strain that can be applied to produce fish sauce with overall sensory characteristics of traditional fish sauce in shorter time.     

Physical Properties and Fatty Acid Profiles of Oils from Black,Kidney, Great Northern,and Pinto Beans

Four common beans (black, kidney, great northern, and pinto) were extracted with hexane and found to contain about 2% triacylglycerols. The fatty acids in these bean oils were mainly linolenic (41.7–46 wt%), linoleic (24.1–33.4 wt%), palmitic (10.7–12.7 wt%) and oleic (5.2–9.5 wt%). Because of the high levels of polyunsaturated fatty acids, the bean oils had iodine values between 174 and 177 g/100 g (compared to 130 g/100 g for soybean oil). Yet, the bean oils exhibited high oxidative stability due to the presence of high amounts of tocopherols (2,670–2,970 ppm). The bean oils had lower pour points (−18 to −11 °C) compared to −9 °C for soybean oil. Among the four bean oils, kidney bean oil had the highest acid value (15.4 mg KOH/g) and kinematic viscosities over a wide range of temperatures.     

Source and changes of proteinase activities of Indian anchovy (Stolephorus spp.) during fish sauce fermentation

Trypsin‐like proteinases exhibited the highest activity in viscera and muscle of Indian anchovy (Stolephorus spp.). The molecular weights (MWs) of proteinases in viscera were estimated to be 31, 35, 44, 49 and 57 kDa by activity staining in the presence of 4 mol L^?1 NaCl. The MW of proteinase extracted from muscle was 56 kDa. This reflects that only one proteinase was extracted from muscle whereas five proteinases were extracted from viscera. Trypsin‐like, chymotrypsin‐like and cathepsin L‐like proteinases were found in commercial fish sauce samples throughout 12 months of fermentation, suggesting that these proteinases were stable at high salt concentrations (250–300 g kg^?1 NaCl) and under acidic conditions (pH 5.2–5.8). In contrast, leucine aminopeptidase activity was detected only in the first month. The MWs of proteinases found in fish sauce after various fermentation periods were estimated to be 37, 47 and 53 kDa, which coincided with the MWs of proteinases found in Indian anchovy. Copyright © 2006 Society of Chemical Industry     

Autolytic activity and biochemical characteristics of endogenous proteinases in Indian anchovy (Stolephorus indicus)

Maximum autolytic activity of Indian anchovy (Stolephorus indicus) was found at 60 °C. Autolytic activity decreased with increased NaCl concentration. Remaining autolytic activity at 25% NaCl (w/w) was 52%. Crude proteinase extracts exhibited the highest activity at 60 °C, using either casein or acid-denatured hemoglobin (dHb) as a substrate. Optimal pH of crude extracts was found at 8.5 for casein and 9.5 for dHb. Activity of crude extract decreased >50% when NaCl concentration was greater than 0.1 M. Crude extract was stable for up to 8 h at 4, 30, and 60 °C. Crude proteinase hydrolyzed several synthetic substrates of trypsin, including Boc-Asp(oBzl)-Pro-Arg-MCA, Boc-Val-Leu-Lys-MCA, and Boc-Gln-Ala-Arg-MCA. Soybean trypsin inhibitor (SBTI), leupeptin, phenylmethanesulfonyl fluoride (PMSF), and N-tosyl-l-lysine chloromethyl ketone (TLCK) inhibited activities of proteinase, indicating trypsin-like characteristics. Molecular weight of proteinases exhibiting caseinolytic activity at 4.0 M NaCl were estimated to be 63, 53, 46, 40, 35, and 31 kDa, using electrophoresis activity staining.     

Effects of hydrogen peroxide and of sulphite and humidity on the amino acid composition and digestibility of fish protein

Cooked saithe fillets were minced and treated with different concentrations of hydrogen peroxide for varying times. The amino acid composition of the protein was not affected except that methionine was oxidised to methionine sulphoxide. Apparent protein digestibility as determined with rats was slightly decreased at the highest hydrogen peroxide level. This effect was not predicted by a rapid enzyme test. Sodium sulphite added to freeze-dried saithe flesh which was kept at three different humidities, had little effect on the amino acid composition. The rationale for this part of the experiments was that auto-oxidating sulphite may oxidise methionine. In this case the sulphite seemed to protect methionine.     

Issues in the mining of heart failure datasets

This paper investigates the characteristics of a clinical dataset using a combination of feature selection and classification methods to handle missing values and understand the underlying statistical characteristics of a typical clinical dataset. Typically, when a large clinical dataset is presented, it consists of challenges such as missing values, high dimensionality, and unbalanced classes. These pose an inherent problem when implementing feature selection and classification algorithms. With most clinical datasets, an initial exploration of the dataset is carried out, and those attributes with more than a certain percentage of missing values are eliminated from the dataset. Later, with the help of missing value imputation, feature selection and classification algorithms, prognostic and diagnostic models are developed. This paper has two main conclusions: 1) Despite the nature of clinical datasets, and their large size, methods for missing value imputation do not affect the final performance. What is crucial is that the dataset is an accurate representation of the clinical problem and those methods of imputing missing values are not critical for developing classifiers and prognostic/diagnostic models. 2) Supervised learning has proven to be more suitable for mining clinical data than unsupervised methods. It is also shown that non-parametric classifiers such as decision trees give better results when compared to parametric classifiers such as radial basis function networks(RBFNs).     

Accelerated Cheddar Cheese Ripening with an Aminopeptidase Fraction from Squid Hepatopancreas

ABSTRACT: An aminopeptidase (AP) fraction from squid (Illex illecebrosus) hepatopancreas was added to Cheddar cheese at 2 levels, and its influence on ripening indices was determined for up to 3-mo storage at 11 °C. Two commercial enzymes (Neutrase ® and Flavourzyme ®) were similarly tested. Cheese with the higher level of squid AP contained more soluble N, amino acids, and Cheddar flavor after 1 mo, but it developed defects in texture and bitterness as ripening progressed. Cheese with less squid AP did not differ from the control with respect to all ripening indices over 3-mo storage. Ripening Cheddar contains cysteine protease inhibitor(s) that inhibit low levels of squid AP but not Neutrase ® and Flavourzyme ®.