Water adsorption isotherms of microcapsules with hydrolyzed pinhão (Araucaria angustifolia seeds) starch as wall material

Water adsorption isotherms of microcapsules that use pinhão starch as the wall material and β-carotene as the core material were evaluated. Pinhão was chosen as the raw material because it is primarily composed of starch, and in the literature there are few technological aspects with regard to this polymer. Moreover, this wall material has been previously studied and demonstrated good encapsulation properties. Moisture adsorption isotherms were determined at 10, 20 and 30 °C using the gravimetric method. The Peleg model was used to fit the experimental data. The differential enthalpy and entropy of sorption were calculated using moisture sorption data; both decreased as moisture content increased. The enthalpy–entropy compensation theory was applied to adsorption isotherms and the isokinetic temperature was calculated by plotting the differential enthalpy as a function of differential entropy. We found that the adsorption process was enthalpy-controlled, the T_β (352.61 K) was higher than the T_hm (292.77 K), and the process was spontaneous (ΔG = −470.17 J mol⁻¹).     

Thermodynamic properties of moisture desorption of raw pinhão (Araucaria angustifolia seeds)

The seeds of Araucaria angustifolia, named pinhão, are consumed in the south and southeast of Brazil. They are big in size and have high nutritious value. The literature about technological aspects of pinhão is very scarce and there are no reports about moisture sorption models. In this work, moisture desorption isotherms of raw pinhão were determined at 15, 25, 30 and 40 °C. Results show that temperature has little effect on the sorption behaviour and the Chirife model was found to best represent the experimental data. The isosteric heat of sorption (differential enthalpy) was calculated through direct use of moisture desorption isotherm by applying the Clausius‐Clapeyron equation. The differential enthalpy of desorption decreased with increasing moisture content. The enthalpy–entropy compensation theory was applied to desorption isotherms and plots of differential enthalpy vs. differential entropy for pinhão provided the isokinetic temperature, indicating an enthalpy‐controlled desorption process.     

Glass transition and state diagram for freeze-dried Agaricus bisporus

Sorption isotherms and state diagram of freeze-dried Agaricus bisporus were developed to further investigate the connection between the two distinct criteria of food stability. Sorption isotherms of freeze-dried A. bisporus were determined by the gravimetric method and the data were modeled by GAB model. The GAB monolayer moisture content was calculated to be 6.2 g/100 g (d.b.). The glass transition temperature of freeze-dried A. bisporus was determined by differential scanning calorimetry. The state diagram was composed of the freezing curve and glass transition line, which were fitted according to Clausius–Clapeyron model and Gordon–Taylor model, respectively. The state diagram yielded maximally-freeze-concentrated solutes at 0.704 solids with the characteristic temperature of glass formation being −77.9 °C. The state diagram and sorption isotherms of freeze-dried A. bisporus are useful in evaluating the storage stability as a function of temperature and moisture content as well as optimizing drying and freezing conditions.     

Sorption isotherms and thermodynamics of water sorption of ready-to-use Basundi mix

Basundi mix representing powdered Basundi (an Indian traditional milk product somewhat similar to sweetened condensed milk) is a convenience product developed for enhanced shelf life at ambient temperature. Water sorption isotherms were obtained for this ready-to-use mix over the temperature range of 5-45 °C. There was definite inversion of the temperature effect at high water activity (>0.7). GAB model gave excellent agreement between experimental and predicted values. Other properties of sorbed water viz., monolayer water, number of adsorbed monolayers, density and amount of bound water and surface area of adsorption were also obtained. The net isosteric heat of sorption had strong dependence on moisture content. The enthalpy-entropy compensation suggested that the sorption mechanism involved is enthalpy driven over the entire range of moisture content studied.     

Muscle lipids and fatty acid profiles of three edible fish from the Mauritanian coast: Epinephelus aeneus, Cephalopholis taeniops and Serranus scriba

Muscle lipids and fatty acids (FA) of three largely consumed seawater species of Serranidae (Epinephelus aeneus, Cephalopholis taeniops, and Serranus scriba) from the Mauritanian coast, were determined through 1 year. The lipid contents were relatively poor, ranging from 0.8% to 2.3% showing a significant seasonal dependency. Amongst the 35 FA identified, 35–51% were saturated FA (SFA), 21–33% monounsaturated FA (MUFA), and 18–34% polyunsaturated FA (PUFA). Palmitic acid was found to be the main SFA, and was seasonal dependent, with a mean value of 30.5% for E. aeneus, 27.9% for C. taeniops, and 20.9% for S. scriba. Amongst MUFA, oleic acid, with 11–16%, was the main acid in all three species. The n6 PUFA level was low, in particular for C. taeniops (1.3–1.6%), and a little higher for S. scriba (3.6–4.2%). The three species were characterised by high amounts of n3 PUFA. Amongst them, docosa-4,7,10,13,16,19-hexaenoic acid (DHA, 22:6n3) was the highest with 5–9% for C. taeniops, 13–17% for S. scriba, and 10–16% for E. aeneus. Eicosa-5,8,11,14,17-pentaenoic acid (EPA, 20:5n3), was the second highest n3 PUFA, with 4–13%.     

Physicochemical properties of Pinhão (Araucaria angustifolia, Bert, O. Ktze) starch phosphates

Physicochemical properties of pinhão (seeds of Paraná pine) starch phosphates were evaluated and compared to corn starch phosphates. The phosphorylation process used yielded starch phosphates with three different degrees of substitution (DS): low (0.015), medium (0.07) and high (?0.12). Medium and high DS starch phosphates had higher cold water binding capacity, swelling power, and paste clarity, but lower paste syneresis (at 5 °C and after freeze-thaw cycles) than native starches (P<0.05). Low, medium, and high DS corn starches had higher solubility than native starches (3.8-, 8-, and 6-fold higher; P<0.05), but the solubility of pinhão starch increased only in medium DS starch phosphates (3-fold higher; P<0.05). Low DS starch phosphates had viscosity curves similar to native starches. In contrast, medium and high DS starch pastes had peak viscosity at room temperature, reached the minimum viscosity when heated to 95 °C, and had low setback.     

Characterization of bacteriocins produced by two strains of Lactobacillus plantarum isolated from Beloura and Chouriço, traditional pork products from Portugal

Bacteriocins bacST202Ch and bacST216Ch, produced by Lactobacillus plantarum strains isolated from Beloura and Chouriço, respectively, inhibited the growth of a number of Gram-positive and Gram-negative meat spoilage bacteria. According to trycine–SDS–PAGE, bacST202Ch and bacST216Ch are approximately 3.5 and 10.0 kDa in size, respectively. Maximal activity of bacST202Ch (25,600 AU/ml) was recorded after 27 h of and bacST216Ch (102,400 AU/ml) after 22 h of growth. The mode of activity, as determined against Enterococcus faecium HKLHS, is bactericidal. Both peptides adsorb to the surface of the producer cells, but at very low concentrations. Both peptides remained active after 120 min at 100 ^oC and after 2 h of incubation at pH 2.0–12.0. Treatment for 120 min at 121 ^oC did not affect bacST216Ch activity. Activity of bacST202Ch and bacST216Ch was not affected by 1% Triton X-100, Tween 80, Tween 20, SDS, NaCl, urea and EDTA. Bacteriocin ST216Ch was deactivated in the presence of 1% Triton X-114. The nucleotide sequence of a 1044 bp DNA fragment amplified from L. plantarum ST202Ch is identical to the structural gene encoding pediocin PA-1, suggesting that the two bacteriocins are identical. Based on the broad spectrum of antibacterial activity, strains ST202Ch and ST216Ch may be used as starter cultures in the fermentation of meat products.     

Characterization of starch nanoparticles obtained from Araucaria angustifolia seeds by acid hydrolysis and ultrasound

Native starch (NS) extracted from the seeds of pinhão (Araucaria angustifolia) was modified by two methods: acid hydrolysis (AH) and ultrasound (US). The three starch samples were subjected to spray drying and characterized. Chemical composition and rheological characteristics were evaluated and morphology was analyzed by scanning electron microscopy. The starch modified by US and AH achieved nanometric size, with mean particle size of about 453 and 22 nm, respectively. Besides the modified starch reached nanometric size, the three starch preparations were significantly different in four characteristics: starch and amylose content, the percentage of syneresis and colorimetric data. The AH sample differed from the others in terms of solubility (more soluble), hygroscopicity (more hygroscopic) and paste clarity (more translucent). Modified starch nanoparticles obtained by AH and US can be useful for development of novel biocomposites with improved properties to be employed as coating materials or films.     

Effect of damaged starch on acrylamide formation in whole wheat flour based Indian traditional staples, chapattis and pooris

Variation in acrylamide content of two Indian traditional products, chapatti and poori was observed with respect to the damaged starch content in whole wheat flour of different wheat varieties from which these products were prepared. Wheat cultivar ‘lokwan’ was milled by altering mill aperture, feed rate and moisture content to obtain whole wheat flour with damaged starch contents ranging from 6.23% to 28.12%. Acrylamide content of the chapatti and pooris prepared from such flours ranged from 12.5 to 65.5 μg/kg in chapatti, and 25.5 to 130.5 μg/kg in pooris. Impact of several additives showed 10 μmol/g flour citric acid, and 100 μmol/g flour calcium chloride to reduce acrylamide in pooris by approximately 54% and 72%, respectively, without altering the sensory analysis of the products.     

Characteristics of native and enzymatically hydrolyzed Zea mays L., Fritillaria ussuriensis Maxim. and Dioscorea opposita Thunb. starches

Comparative studies on glucoamylase hydrolysis of A-type Zea mays L., B-type F. ussuriensis Maxim., and C-type Dioscorea opposita Thunb. were carried out by scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared (FT-IR) spectra and differential scanning calorimetry (DSC). Maize, Fritillaria, Dioscorea starches were hydrolyzed with glucoamylase for 2, 4, 8, 12 and 24 h, respectively. The SEM and XRD results revealed that A-type, B-type starch and C-type starch displayed different hydrolysis mechanisms. A-type starch was digested with enzyme penetrating into starch granules through natural pores on the surface and disrupted the interior of the starch granules. The glucoamylase worked by attacking the surface of B-type starch and forming cracks. When endo-corrosion occurred, the internal part of the granule was corroded through small cracks. However, the glucoamylase primarily attacked the interior of the C-type starch granules and then the exterior of starch granules. FT-IR confirmed that the amorphous regions in the starch granules are firstly hydrolyzed and could be hydrolyzed completely as long as the hydrolysis time is sufficient. The transition temperatures and enthalpy of gelatinization (ΔH_gel) were determined using DSC. According to the gelatinization parameters, it could be further proved amorphous and crystalline structures were hydrolyzed.     

Chemical compositions,fine structure and physicochemical properties of kudzu (Pueraria lobata) starches from different regions

Three commercial kudzu starches from Vietnam, Japan and Korea were used to determine chemical compositions, isoflavone compounds, fine structure and physicochemical properties. The kudzu starch from Vietnam had polygonal granules, whereas the kudzu starches from Japan and Korea contained both polygonal and spherical granules. Total protein, lipid, ash and phosphorus contents present in these kudzu starches were less than 1% (starch basis). The kudzu starch from Vietnam and Korea contained both daidzein and daidzin, whereas the kudzu starch from Japan had only daidzein. These starches had similar actual amylose contents (22.2–22.9%). However, λ_max, blue value and apparent amylose contents of the kudzu starch from Vietnam were lower than those from Japan and Korea. Amylose molecules of the kudzu starch from Vietnam had the largest average degree of polymerization (DP_n) and number of chains (NC), followed by the kudzu starches from Japan and Korea. Amylopectin molecules of the kudzu starch from Vietnam also had the largest DP_n and NC, followed by the kudzu starches from Korea and Japan. X-ray diffraction patterns of the kudzu starches from Vietnam, Japan and Korea were A-type, C-type and B-type, respectively. The kudzu starch from Vietnam was found to have the specific characteristics such as significantly high gelatinization temperature, transition enthalpy and degree of crystallinity as compared to the kudzu starch from Korea and Japan.     

Studies on use of Enteromorpha in snack food

Seaweeds, also known as sea vegetables, are of nutritional interest, as they are rich in vitamins, minerals and dietary fiber. Enteromorpha compressa (Linnaeus), green seaweed (chlorophyta), which is a rich source of iron and dietary fibre was used as an ingredient in the preparation of Pakoda, a common traditional snack food in India. Pakoda samples showed increases in ash, protein and total dietary fibre contents with increase in Enteromorpha level, accompanied by a nearly fivefold increase in iron content (26.4–126 mg/100 g) and fourfold increase in calcium content (30.1–124 mg/100 g). Bioavailability of iron in Enteromorpha, and Pakoda containing 7.5% of Enteromorpha, did not show any difference (55–56%) at pH 7.5 (intestinal condition). But, at pH 1.35 (gastric condition) the bioavailability of iron in Pakoda containing Enteromorpha was found to be slightly higher (27.1%) than that in Enteromorpha. Reducing power (155–222 μg/g) increased as the Enteromorpha level increased from 0% to 15%. But the addition of Enteromorpha was found to decrease free radical-scavenging activity and the total phenol content. Pakoda containing up to 7.5% of Enteromorpha was found to have a sensory quality comparable with that of Pakoda without Enteromorpha.     

Characterization of new starches separated from different Chinese yam (Dioscorea opposita Thunb.) cultivars

The starches separated from four different Dioscorea opposita Thunb. cultivars were investigated for morphological, thermal, crystal, and physicochemical properties, such as amylose content, swelling power, solubility and water-binding capacity properties. Amylose content of D. oppositastarches from different cultivars ranged from 20.74% to 25.94%. The shape of starch granules separated from different D. opposita Thunb. cultivars varied from round to oval or elliptic. The mean particle diameter of starches ranged from 23.39 to 26.87 μm. The transition temperatures (T_o, T_p and T_c) and enthalpy of gelatinization (ΔH_gel) were determined using differential scanning calorimetry (DSC). T_o, T_p and T_c varied from 73.6 to 74.8, 78.8 to 81.0, and 83.3 to 87.2 °C, respectively. D. opposita cv. Jinchengerhao starch showed the highest ΔH_gel values (12.48 J/g) while D. opposita cv. Baiyu starch showed the lowest values (8.413 J/g). The crystal type of starches separated from different D. opposita cultivars was a typical C_B-type pattern. The degrees of crystallinity of the four D. opposita cultivars starches were about 50.52%, 32.99%, 33.57% and 36.16%, respectively.     

MOISTURE SORPTION CHARACTERISTICS of STARCH GELS. PART II: THERMODYNAMIC PROPERTIES

A thermodynamic approach was used to interpret the experimental adsorption and desorption isotherm data for potato starch gel. Calculation of the thermodynamic properties (differential enthalpy, integral enthalpy, differential entropy and integral entropy) provides an understanding of the properties of water and energy requirements associated with the sorption behavior. Isosteric heats (differential enthalpies) were calculated through direct use of moisture isotherms by applying the Clausius‐Clapeyron equation. the differential enthalpy and entropy decreased with increasing moisture content and were adequately characterized by an exponential model. A plot of differential heat versus entropy satisfied the enthalpy‐entropy compensation theory. the spreading pressure increased with increasing water activity, and decreased with increasing temperature. the net integral enthalpy increased with moisture content to a maximum value (around the monolayer moisture content) and then decreased. In a reverse manner, the net integral entropy decreased with moisture content to a minimum value and then increased.     

Enthalpy–entropy compensation in sorption phenomena of starch materials

The enthalpy–entropy compensation theory was applied to the experimental moisture adsorption and desorption isotherm data (water activity (a_w) range 0.006–0.982) of raw potato, potato starch gel, potato starch powder, highly amylopectin corn starch powder and highly amylose corn starch powder in the temperature range 30–60 °C. A linear relation existed between differential enthalpy (ΔH) and differential entropy (ΔS) for all the experimental data considered, thus satisfying the enthalpy–entropy compensation theory. Further analysis of the data indicated an enthalpy-controlled (isokinetic temperature (T_β) > harmonic mean temperature (T_hm)) and spontaneous (−ΔG) sorption process.     

Variations in essential oil and fatty acid composition during Myrtus communis var. italica fruit maturation

The essential oil and fatty acid composition of Myrtus communis var. italica fruit during its ripening was determined. The effect of the harvesting time on some physical properties of Myrtus fruits, fruit weight and moisture content, were significant. The increase of fruit weight (from 2.54 to 8.79 g% fruits) during ripeness was correlated positively with that of moisture content (from 28% to 72%). Fruit essential oil yields varied from 0.003% to 0.01% and showed a remarkable increase at 60 days after flowering to reach a maximum of 0.11%. Forty-seven volatile compounds were identified in fruit essential oils; 1,8-cineole (7.31–40.99%), geranyl acetate (1.83–20.54%), linalool (0.74–18.92%) and α-pinene (1.24–12.64%) were the main monoterpene compounds. Total fatty acid contents varied from 0.81% to 3.10% during fruit maturation and the predominant fatty acids were linoleic (12.21–71.34%), palmitic (13.58–37.07%) and oleic (6.49–21.89%) acids. The linoleic acid proportions correlated inversely with palmitic and oleic acids during all the stages of ripening.     

Studies on the physicochemical,morphological, thermal and crystalline properties of starches separated from different Dioscorea opposita cultivars

The physicochemical, morphological, thermal and crystal properties of the starches separated from four different Dioscorea opposita Thunb. cultivars (Taigu, Ribenbai, Wenxi and Zhongbowen) were studied. Amylose contents of D. opposita Thunb. starches from different cultivars ranged from 21.17% to 25.00%. The shape of starch granules separated from different D. opposita Thunb. cultivars varied from round or oval to elliptic or caky. The surface of the starch granules appeared to be smooth without any fissures. The average particle diameter of starches from different D. opposita Thunb. cultivars ranged from 25.90 to 28.06 μm. The transition temperatures (T_o, T_p and T_c) and enthalpy of gelatinization (ΔH_gel) were determined using differential scanning calorimetry (DSC). T_o, T_p, T_c and ΔH_gel of D. opposita Thunb. starches ranged from 73.1 to 73.9, 77.6 to 80.4, 82.1 to 85.9 °C and 6.548 to 12.13 J/g, respectively. The crystal type of starches separated from different D. opposita Thunb. cultivars was a typical C-type pattern. The relative degree of crystallinity of the four D. opposita Thunb. cultivars starches were about 38.79%, 39.88%, 41.67% and 49.03%, respectively.     

Heavy metal levels in two fish species Leuciscus cephalus and Lepomis gibbosus

The concentrations of heavy metals (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) were measured in muscle, gill and liver of two fish species (Leuciscus cephalus and Lepomis gibbosus) caught from Saricay, South-West Anatolia. Levels of metals varied depending on different tissues in species. The mean concentrations (μg g⁻¹ wet weight) of heavy metals in tissues of Leucis cephalus were as follows: Cd: 0.010–0.084, Co: nd–0.131, Cu: 0.193–2.611, Fe: 4.240–172.000, Mn: 0.112–24.230, Pb: 0.068–0.874, Zn: 6.350–28.550, and in tissues of Lepomis gibbosus were as follows; Cd: 0.008–0.082, Co: nd–0.233, Cu: 0.065–4.360, Fe: 11.200–125.000, Mn: nd–12.434, Pb: 0.070–0.920, Zn: 6.540–16.064. Ni was not determined in all organs studied.     

Gene dosage effect on starch structure studied using maize polygenic model containing ae and su1 mutant alleles

The aim of this work was to enhance our understanding on the gene dosage effect on starch structure. Two mutant alleles, ae and su1, were selected for this study. With regard to their genetic functions, ae and su1 mutations are at two opposite extremes; therefore ae and su1 constituted an ideal pair of mutant alleles for manipulating starch structures. A full set of dosage combinations of ae and su1 were constructed in the maize W64A inbred line, and matured kernels were subjected to starch structure analysis. Scanning electron microscopy showed that starch granule morphology was affected by high doses of ae and su1 alleles. X-ray powder diffraction showed that 3 doses of su1 were not able to change the crystalline pattern of starch, whereas 3 doses of ae transformed A-type pattern to B-type. Size-exclusion chromatography showed that homozygous ae, su1, and ae su1 led to drastic change of starch structure from that of non-mutant. In addition, starches from certain ae and su1 dosage combinations were different from those of homozygous genotypes. This study will lay further foundation towards genetic modification of starch for desirable functional properties in food.