Uncooked Samples Research Articles

Study on sound-speed dispersion in a sandy sediment at frequency ranges of 0.5–3 kHz and 90–170 kHz

In order to study the properties of sound-speed dispersion in a sandy sediment, the sound speed was measured both at high frequency (90–170 kHz) and low frequency (0.5–3 kHz) in laboratory environments. At high frequency, a sampling measurement was conducted with boiled and uncooked sand samples collected from the bottom of a large water tank. The sound speed was directly obtained through transmission measurement using single source and single hydrophone. At low frequency, an in situ measurement was conducted in the water tank, where the sandy sediment had been homogeneously paved at the bottom for a long time. The sound speed was indirectly inverted according to the traveling time of signals received by three buried hydrophones in the sandy sediment and the geometry in experiment. The results show that the mean sound speed is approximate 1710–1713 m/s with a weak positive gradient in the sand sample after being boiled (as a method to eliminate bubbles as much as possible) at high frequency, which agrees well with the predictions of Biot theory, the effective density fluid model (EDFM) and Buckingham’s theory. However, the sound speed in the uncooked sandy sediment obviously decreases (about 80%) both at high frequency and low frequency due to plenty of bubbles in existence. And the sound-speed dispersion performs a weak negative gradient at high frequency. Finally, a water-unsaturated Biot model is presented for trying to explain the decrease of sound speed in the sandy sediment with plenty of bubbles.

Bioactive potential of the wild mushroom Astraeus hygrometricus in South-west India

ABSTRACTThe wild mushroom Astraeus hygrometricus is a traditional delicacy during the monsoon season in South-western India. Bioactive principles and antioxidant potential of uncooked and pressure-cooked tender mushroom have been evaluated. Seven bioactive principles of mushroom (tannins, flavonoids, vitamin C, phytic acid, lycopene, β-carotene and trypsin inhibition) were significantly higher, while total phenolics content was significantly lower in uncooked than in cooked samples. Mushroom was devoid of L-DOPA, whereas only uncooked samples showed haemagglutinin activity against A+ blood group. The principal component analysis of uncooked mushroom showed only two bioactive principles clustered with two antioxidant properties, while in cooked mushroom five bioactive principles clustered with three antioxidant properties depicting the nutraceutical potential of cooked mushroom. Future studies should focus on appropriate thermal treatment, which retain maximum bioactive and antioxidant potential to combat health- and lifestyle-related ailments. The A. hygrometricus is ectomycorrhizal, conservation of its host tree species is utmost importance in improvement and expansion of its yield to sustain food security and economic gains of local tribals.

Study of drying process on starch structural properties and their effect on semolina pasta sensory quality

The influence of drying temperature on the starch crystallites and its impact on durum wheat pasta sensory properties is addressed in this work. In particular, spaghetti were produced by means of a pilot plant using 5 different drying temperature profiles. The sensory properties, as well as the cooking quality of pasta were assessed. X-ray powder diffraction was used for investigating changes in the crystallinity content of the samples. Starch crystallinity, size and density of the starch crystallites were determined from the analysis of the diffraction profiles. As expected, spaghetti sensory properties improved as the drying temperatures increased. In particular, attributes as resistance to break for uncooked samples and firmness, elasticity, bulkiness and stickiness for cooked samples, all benefit from drying temperature increase. The spaghetti cooking quality was also positively affected by the drying temperature increase. Diffraction analysis suggested that the improvement of sensory properties and cooking quality of pasta were directly related to the increase in density of both physical crosslink of starch granules and chemical crosslink of protein matrix.

Changes in Soluble Protein Fractions of Rice Varieties after Cooking by Different Methods

The aim of this research was to study the changes in soluble protein fractions of six rice varieties cooked by four cooking methods viz. ordinary, pressure, microwave and solar cooking methods. In cooked rice albumin, globulin, prolamin and glutelin fractions ranged from 4.1 to 4.3, 11.6 to 12.2, 3.0 to 3.6 and 80.5 to 81.0 % under various cooking methods against 6.4, 14.6, 4.6 and 74.4 % in the uncooked samples. Results indicated that albumin, globulin and prolamin fractions decreased significantly after cooking. This decrease was accompanied by a significant increase in the glutelin fraction as compared to uncooked rice samples. Among cooking methods, albumin in pressure and solar, globulin in solar and prolamin in ordinary were significantly (P<0.05) higher than other methods. However, in respect of glutelin content microwave and solar cooking methods were superior to ordinary but at par to pressure cooking method.

Effect of Deep-Frying or Conventional Oven Cooking on Thermal Inactivation of Shiga Toxin–Producing Cells of Escherichia coli in Meatballs

We investigated the effects of deep-frying or oven cooking on inactivation of Shiga toxin-producing cells of Escherichia coli (STEC) in meatballs. Finely ground veal and/or a finely ground beef-pork-veal mixture were inoculated (ca. 6.5 log CFU/g) with an eight-strain, genetically marked cocktail of rifampin-resistant STEC strains (STEC-8; O111:H, O45:H2, O103:H2, O104:H4, O121:H19, O145:NM, O26:H11, and O157:H7). Inoculated meat was mixed with liquid whole eggs and seasoned bread crumbs, shaped by hand into 40-g balls, and stored at -20°C (i.e., frozen) or at 4°C (i.e., fresh) for up to 18 h. Meatballs were deep-fried (canola oil) or baked (convection oven) for up to 9 or 20 min at 176.7°C (350°F), respectively. Cooked and uncooked samples were homogenized and plated onto sorbitol MacConkey agar with rifampin (100 μg/ml) followed by incubation of plates at 37°C for ca. 24 h. Up to four trials and three replications for each treatment for each trial were conducted. Deep-frying fresh meatballs for up to 5.5 min or frozen meatballs for up to 9.0 min resulted in reductions of STEC-8 ranging from ca. 0.7 to ≥6.1 log CFU/g. Likewise, reductions of ca. 0.7 to ≥6.1 log CFU/g were observed for frozen and fresh meatballs that were oven cooked for 7.5 to 20 min. This work provides new information on the effect of prior storage temperature (refrigerated or frozen), as well as subsequent cooking via deep-frying or baking, on inactivation of STEC-8 in meatballs prepared with beef, pork, and/or veal. These results will help establish guidelines and best practices for cooking raw meatballs at both food service establishments and in the home.

Cooking Treatment Effects on Sugar Profile and Sweetness of Eleven-Released Sweet Potato Varieties

Cooking can significantly alter sugar content of sweet potato roots. Sweet potato roots were processed using three different cooking treatments, with the aim of investigating the effects of these methods on sugar profile and sweetness levels. Significant contribution of the cooking treatment and genotype, and their interaction on levels of the sugars were also determined. Moreover, sugar values were converted to relative sweetness per sucrose equivalent. The results revealed that cooking treatment produced the highest effect on sugar except fructose. Variability due to the interactions was significant and ranged from 2.60% to 11.74%. Whilst sucrose was the predominant in the raw form, maltose increased dramatically during cooking. Sweetness level increased substantially upon cooking and was highly dependent on initial sugar content, amylase activity and cooking treatment. Thus, evaluation of sweetness levels in sweet potato clones should not only be on the uncooked samples but should take into account the cooking methods employed.

Effect of cooking procedures on tylosin residues in chicken meatball

Most information about drug residues is related to their concentrations in raw products. The objective of this study was to assess the effects of various microwave and boiling treatments on the stability of different concentrations of tylosin in chicken meatballs. The chicken meatball samples (75 g) were prepared and fortified by 3 concentrations of tylosin (100, 200 and 300 μg kg−1) and were cooked by boiling (100 °C for 10, 20, 30 min) and microwave procedure (power 450 W for 1, 1.5 and 2 min). The tylosin content was measured in raw and cooked samples through the use of high performance liquid chromatography. The microwave and the boiling process significantly reduced the tylosin. In both procedures, there were negative correlations between the length of cooking time and the reduction percentage of tylosin. In addition, tylosin reduction percentage in chicken meatball cooked by boiling depended on its concentration in uncooked samples. There was a relationship between tylosin reduction percentage and the increase in the internal temperature and weight loss during the cooking process. The results of this study indicate that tylosin residues in the food are decreased during the cooking process. Thus, given that a food product is cooked to be consumed, the surveillance of data obtained from tylosin measurement in the raw tissues samples could not be considered as consumers’ exposure to tylosin via dietary intake.

The Effects of Potato Puree and Bread Crumbs on Some Quality Characteristics of Low Fat Meatballs.

The purpose of this study was to determine the effects of using different amounts of potato puree (PP) (10 or 20%) and 10% bread crumbs (BC) as an extender and also control samples (C) with no added extender on chemical composition, energy values, cooking analyses, colour measurements, water holding capacity (WHC), penetration values, thiobarbituric acid value (TBA) and sensory analyses of meatballs. Meatball samples were cooked in a pre-heated 180℃ electric oven. Uncooked meatballs formulated with 20% PP had the highest moisture content. No significant differences were recorded for protein contents of uncooked samples. The highest cooking yield was found in samples extended with 10% BC. Increasing PP from 10% to 20% increased cooking yield of meatballs. 20% PP increased moisture and fat retention values and water holding capacity of meatballs. Meatballs with 10% BC had the lowest (the hardness in the texture) and meatballs with the 20% PP had the highest (the softness in the texture) penetration values. Formulating meatballs at a level of 20% resulted lower L* values. TBA values of control samples were higher than in PP added samples at the end of the storage period. Flavour scores for meatballs formulated with PP were higher than control and meatballs formulated with BC. Meatballs formulated with 10% PP had similar overall acceptability with meatballs added with 10% BC.

Effect of Domestic Cooking Methods on Antioxidant Capacity of Fresh and Frozen Kale

The aim of this study was to evaluate the changes in the antioxidant capacity of fresh and frozen kale during domestic cooking methods (e.g., boiling, microwaving, and steaming). The antioxidant activities of the samples were measured using three in vitro assays (1,1-diphenyl-2-picrylhydrazyl assay, 2, 2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid assay, and ferric reducing antioxidant power assay). The steaming treatment was found to be the best cooking method to retain antioxidant compounds, followed by the microwaving and boiling treatments. The frozen uncooked samples exhibited a higher antioxidant capacity than the fresh, uncooked samples, indicating that the freezing process could enhance the antioxidant capacity of the kale.

Influence of customized cooking methods on the phenolic contents and antioxidant activities of selected species of oyster mushrooms (Pleurotus spp.).

Nutritional value of cooked food has been considered to be lower compared to the fresh produce. However, many reports showed that processed fruits and vegetables including mushrooms may retain antioxidant activity. Pleurotus spp. as one of the edible mushroom are in great demand globally and become one of the most popular mushrooms grown worldwide with 25-fold increase in production from 1960-2009. The effects of three different cooking methods (boiling, microwave and pressure cooking) on the antioxidant activities of six different types of oyster mushrooms (Pleurotus eryngii, P citrinopileatus, P. cystidiosus P. flabellatus, P. floridanus and P. pulmonarius) were assessed. Free radical scavenging (DPPH) and reducing power (TEAC) were used to evaluate the antioxidant activities and the total phenolic contents were determined by Folin-Ciocalteu reagent. Pressure cooking improved the scavenging abilities of P. floridanus (>200%), P. flabellatus (117.6%), and P. pulmonarius (49.1%) compared to the uncooked samples. On the other hand, the microwaved Pleurotus eryngii showed 17% higher in the TEAC value when compared to the uncooked sample. There was, however, no correlation between total phenolic content and antioxidant activities. There could be presence of other bioactive components in the processed mushrooms that may have contributed to the antioxidant activity. These results suggested that customized cooking method can be used to enhance the nutritional value of mushrooms and promote good health.

Cooking Chicken Breast Reduces Dialyzable Iron Resulting from Digestion of Muscle Proteins.

The purpose of this research was to study the effect of cooking chicken breast on the production of dialyzable iron (an in vitro indicator of bioavailable iron) from added ferric iron. Chicken breast muscle was cooked by boiling, baking, sautéing, or deep-frying. Cooked samples were mixed with ferric iron and either extracted with acid or digested with pepsin and pancreatin. Total and ferrous dialyzable iron was measured after extraction or digestion and compared to raw chicken samples. For uncooked samples, dialyzable iron was significantly enhanced after both extraction and digestion. All cooking methods led to markedly reduced levels of dialyzable iron both by extraction and digestion. In most cooked, digested samples dialyzable iron was no greater than the iron-only (no sample) control. Cooked samples showed lower levels of histidine and sulfhydryls but protein digestibility was not reduced, except for the sautéed sample. The results showed that, after cooking, little if any dialyzable iron results from digestion of muscle proteins. Our research indicates that, in cooked chicken, residual acid-extractable components are the most important source of dialyzable iron.

Encapsulated amylosucrase‐treated starch with enhanced thermal stability: Preparation and susceptibility to digestion

AbstractUnderstanding in vitro digestibility and release experiments with starch‐entrapped calcium alginate microspheres provide the possibility of controlling starch digestibility in the human gastrointestinal tract. Native and amylosucrase (AS)‐treated waxy corn starches (5000 U, 20 000 U, and control) were encapsulated with three different ratios of sodium alginate: 0.5, 0.7, and 1.0%. The slowly digestible and RS fractions of the encapsulated starch were 57.5 and 97.7%, respectively. After cooking, the proportions of these fractions still ranged from 55.7 to 96.1%, depending on the type of starch and concentration of sodium alginate, whereas the un‐encapsulated starch contained between 2.9 and 48.3% slowly digestible and RS after cooking. In vitro release was studied in both uncooked and cooked encapsulated samples. When incubated in simulated gastric fluid, the beads swelled and started to float but did not erode, even after thermal treatment. Incubation in simulated intestinal and colonic fluids caused the beads to release starch in both uncooked and cooked starch‐encapsulated samples. Encapsulated AS control and native waxy corn starch samples released much more starch than AS‐modified starches. The total amount of starch released did not exceed 20% for uncooked samples and 25% for cooked samples.

The influence of cooking process on the microwave-assisted extraction of cottonseed oil.

Cooking process is one of the most energy and time consuming steps in the edible oil extraction factories. The main goal of this study was cottonseed oil extraction by microwave radiation and elimination of any heat treatment of cottonseeds before extraction. The effect of cooking process on the physicochemical properties of extracted oil from two varieties of cottonseed (Pak and Sahel) was evaluated by free fatty acid content, melting point, smoke point and refractive index. Our results didn't show any significant differences between cooked and uncooked samples (P > 0.05) regarding physicochemical characteristics. From GC analysis of extracted oils, it was found there is no significant difference in fatty acid composition of cooked, uncooked and control (conventional extraction) samples. The thermal stability (Rancimat) analysis of oil samples showed the cooking process could cause a slight increase in the stability of oils for both varieties (about 40min). The cooking process also increased total extracted phenolic compounds and considerably decreased total gossypol content of the cottonseed oil; but the extraction efficiency didn't change considerably after elimination of the cooking process. It can be concluded that microwave rays can destroy the structure of oil cells during process and facilitate the oil extraction without any heat treatment before extraction.

Microbiological study of spiced chicken burgers in Tripoli City, Libya

We investigated the microbiological quality of uncooked and cooked spiced chicken burger in restaurants and fast food places in Tripoli city and surrounding areas. Thus 120 samples (64 cooked and 56 uncooked) were analysed microbiologically. All the samples were highly contaminated with bacteria: 66.6%, 25.9%, 29.6%, 20.3% and 12.9% of the uncooked samples were contaminated with Escherichia coli, Aeromonas spp., Staphylococcus aureus, E. coli 0157:H7 and salmonella respectively. Additionally 10.9%, 3.1%, 4.68%, 3.12% and 1.56 of the cooked samples were contaminated with E. coli, Aeromonas spp., E. coli 0157:H7, S. aureus and salmonella respectively.

Effect of gamma irradiation and cooking on cowpea bean grains ( Vigna unguiculata L. Walp)

Leguminous plants are important sources of proteins, vitamins, carbohydrates, fibers and minerals. However, some of their non-nutritive elements can present undesirable side effects like flatulence provoked by the anaerobic fermentation of oligosaccharides, such as raffinose and stachyose, in the gut. A way to avoid this inconvenience, without any change in the nutritional value and post-harvesting losses, is an irradiation process. Here, we evaluated the effects of gamma irradiation on the amino acids, thiamine and oligosaccharide contents and on the fungi and their toxin percentages in cowpea bean ( Vigna unguiculata L. Walp) samples. For irradiation doses of 0.0, 0.5, 1.0, 2.5, 5.0 and 10.0 kGy the results showed no significant differences in content for the uncooked samples. However, the combination of irradiation and cooking processes reduced the non-nutritive factors responsible for flatulence. Irradiation also significantly reduced the presence of Aspergillus, Penicilium, Rhizopus and Fusarium fungi and was shown to be efficient in grain conservation for a storage time of 6 months.

Understanding starch organisation in gluten-free pasta from rice flour

Starches extracted from parboiled rice flour and pasta samples produced by two extrusion processes – a conventional method carried out at 50 °C and an extrusion-cooking process at 115 °C – were evaluated by differential scanning calorimetry (DSC) and size exclusion chromatography (SEC) analysis. Molecular changes induced by both pasta-making process and following cooking in boiling water were also investigated using iodine absorption properties of samples expressed as the ratio of absorption to scattering spectra (K/S) and X-ray diffraction. A decrease in polymer chain mobility and iodine binding capacity were observed after pasta-making process. While the characteristic A-type crystalline pattern remained, the exposure to iodine vapor changed the peak intensity of starch samples, especially at 0.97 a w. The higher melting temperature of pasta samples in comparison with parboiled rice flour reflected the decrease in mobility of the amorphous regions detected by K/S spectral analysis. The pasta making-process also affected the molecular size distribution of starch samples. In particular, the elution peak shifted toward lower fraction numbers with increasing extrusion temperature, showing a higher molecular size for starch after the extrusion-cooking. All the differences detected between starch samples according to extrusion conditions were deleted during cooking. Compared to the uncooked samples, starch from cooked pasta showed higher K/S value at all wavelengths, highlighting the increase in mobility of the amorphous region. Moreover, beside the increase in melting temperature, a decrease in endothermic enthalpy was detected, confirming the loss of order observed by X-ray diffraction.

EFFECT OF LUPIN FLOUR SUBSTITUTION ON THE QUALITY AND SENSORY ACCEPTABILITY OF INSTANT NOODLES

ABSTRACT Instant noodles are usually made from wheat flour which is low in protein and dietary fiber contents. To improve the nutritional quality of instant noodles, samples were prepared by incorporating lupin flour, which is high in protein and dietary fiber contents, at 10, 20, 30, 40 and 50% levels. Two sets of noodle samples were made; one with 0.05% added ascorbic acid and the other without added ascorbic acid. The uncooked samples were evaluated for color, protein, fat and mineral contents. The cooked samples were analyzed for cooking loss, color and textural properties in comparison with the control sample. Sensory characteristics (color, flavor, texture, taste and overall acceptability) were also evaluated to find out the optimum acceptable level of lupin flour incorporation in the instant noodles. There was no significant increase in the cooking losses at ≤30% lupin incorporation. The color of both uncooked and cooked noodles became more yellowish with the increase in lupin concentration. However, the addition of ascorbic acid (0.05%) improved the color of cooked instant noodles. The addition of 20% lupin flour improved the nutritional value of the product by increasing protein by 42% and dietary fiber by approximately 200% without affecting the sensory properties of instant noodles. PRACTICAL APPLICATIONSInstant noodles, conventionally prepared from wheat flour, are low in protein and dietary fiber contents. Lupin flour, which is high in protein and fiber contents, has been assessed for its incorporation into instant noodle by means of physical, nutritional and sensory evaluations. The study provides information about a commercially viable way of increasing protein and fiber content in instant noodles.

Cooking Methods and Storage Treatments of Potato: Effects on Carotenoids, Antioxidant Activity, and Phenolics

The influence of genotype, cooking method, and storage treatments on potato compounds associated with improved human health was analyzed. Antioxidant activity (AA), total phenolics (TP), and total carotenoids (xanthophyll carotenoids, CAR) were determined in eight genotypes using 2,2-diphenyl-1-picrylhydrazyl (DPPH), Folin-Ciocalteu reagent, and spectrophotometric absorbance, respectively. Individual phenolic and carotenoid composition was analyzed using high performance liquid chromatography (HPLC) in three genotypes of potato. Samples were subjected to a combination of storage conditions for approximately 4 months (non-stored or stored for 110 days at either 4°C, 4°C with an additional 10 days of reconditioning at 20°C, or 20°C storage) and cooking methods (baking, boiling, frying, or microwaving); an uncooked sample was used as a control. The non-stored samples had lower amounts of CAR, AA, and TP along with the individual compounds compared to the various storage regimes, while the recondition storage treatment produced equal or higher levels of TP and individual phenolics than any other storage regime. No cooking and boiling resulted in significantly lower AA and TP, as compared to baking, frying and/or microwaving. Baking, frying and/or microwaving also increased the levels of chlorogenic acid, caffeic acid, (-) epicatechin, p-coumaric acid and vanillic acid, but decreased quercetin dihydrate when compared to uncooked samples. Most health promoting compounds were enhanced by one or both postharvest processing parameters (storage and cooking); however, t-cinnamic acid, and lutein were not affected.

Alkali-aided protein extraction from chicken dark meat: Textural properties and color characteristics of recovered proteins

Textural properties, water-holding capacity, and color characteristics of alkali-extracted chicken dark meat have been studied. Alkali extraction was carried out at 4 different pH values (10.5, 11.0, 11.5, and 12.0). At higher pH of extraction, cooking loss and water loss were found to be significantly decreased (P < 0.05). The lightness (L* value) of the recovered samples treated at higher pH was found to be significantly lower (P < 0.05). Whiteness of uncooked samples also decreased significantly at higher extraction pH values. Protein samples extracted at higher pH values were found to be harder, and the maximum (4,956 g of force) value was shown by samples prepared at pH 11.5. Chewiness values were significantly increased (P < 0.05) for protein samples extracted at pH values of 11.5 and 12.0. Dynamic viscoelastic behavior of samples was assessed in the temperature range of 7 to 100 degrees C. The dynamic viscoelastic behavior of raw chicken dark meat as revealed by storage modulus indicated considerable gel-forming ability. The maximum storage modulus (G') value of 439 kPa was measured at 66.7 degrees C. Storage modulus was found to decrease for the recovered protein samples and be lowest at higher pH values. However, the recovered protein samples did show substantial gel-forming ability when stored with cryoprotectants. Tan delta values denoted 2 clear transitions for raw dark meat; however, only 1 major transition at 50.1 degrees C was evident for pH-treated samples, probably reflecting the loss of collagen in processing. In conclusion, this process of protein recovery may offer the possibility to use the underused poultry resources for preparation of functional foods.

Inhibition of lipid oxidation and dynamics of polyphenol content in mechanically deboned meat supplemented with sea buckthorn ( Hippophae rhamnoides) berry residues

Mechanically deboned meat (MDM) contains about 10 times more polyunsaturated fatty acids (PUFAs) and also more hemoproteins than hand deboned meat (HDM) and is essentially more susceptible to both chemical and biochemical oxidation. The oxidation, leading to the formation of potentially mutagenic and carcinogenic derivatives of PUFAs, can be inhibited by berry extracts rich in antioxidant polyphenols. Using the 2-thiobarbituric acid reactive substances (TBARS) method, we have established that the ethanol slurry of the juice-free solid residue of sea buckthorn ( Hippophae rhamnoides – SB) berries inhibits oxidation of unsaturated fatty acids, of both chicken and turkey MDM. The polyphenols, mainly flavonols, responsible for this inhibition, are comparatively stable during short-term cooking and 6-day storage of cooked SB-MDMs at +6 °C. About half of the polyphenols are lost, obviously oxidised, during the storage of the uncooked samples of turkey 2%SB-MDM at +6 °C. The loss of polyphenols is much smaller in the case of chicken MDM, which is characterised by an in situ lower content of fatty acids, including the polyunsaturated ones. The liquid chromatography–diode array detection–tandem mass spectrometry (LC–DAD–ESI-MS/MS) method was used for identification and ranking of the potent polyphenolic antioxidants in the berry residue.