• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 2
  • 1
  • Tagged with
  • 13
  • 13
  • 6
  • 5
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Evaluation of Antioxidant Effectiveness and Sensory Attributes of Chinese 5-Spice Ingredients in Cooked Ground Beef

Dwivedi, Saumya 01 May 2005 (has links)
This study determined antioxidant and sensory effects of cinnamon, cloves, fennel, pepper, and star anise (Chinese 5-spice ingredients) in cooked ground beef. In experiment 1, thiobarbituric acid (TBA) values of cooked samples were measured during refrigerated storage. In experiment 2, trained panelists evaluated cooked samples for rancid, beef, and spice flavor intensity. Total aerobic plate counts were also measured. Mean TBA values were high (3.4) for control samples. In previous studies, TBA values >1.0 were associated with unacceptably rancid cooked meats. At the lowest spice level of 0.1% of meat weight, all spices except pepper had lower TBA values than controls. Thus, the minimum effective level was 0.1% for all spices except pepper. For all spices except cloves, increasing the use level to 0.5% significantly decreased TBA values (dose-response effect). Cloves did not exhibit a dose-response effect, since all clove levels were very effective, and not different, for maintenance of TBA values In experiment 2 (sensory evaluation), there was a high positive correlation (p < 0.01) between TBA values and panel scores for rancid odor and flavor (0.83 and 0. 78, respectively). Hence, TBA values were in good agreement with sensory panel scores as a measure of oxidation during storage. Spice flavor was inversely correlated (p < 0.01) with rancid odor and flavor (-0.57 and -0.61, respectively), suggesting that spices also decreased the perception of rancid flavor in these samples. The 5-spice blends did not inhibit microbial growth of cooked samples during storage, compared to controls, perhaps due to heat inactivation or loss of antimicrobial components from the spices during cooking. In conclusion, all spices and blends had a dual effect, reducing chemical oxidation as measured by TBA values, and also imparting a distinctive flavor to cooked ground beef.
2

Sensory and phenolic profiling of Cyclopia species (Honeybush) and optimisation of the fermentation conditions

Theron, Karin Alicia 03 1900 (has links)
Thesis (MSc Food Sc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The sensory profiles, phenolic composition and colour of honeybush infusions, prepared from six Cyclopia species (C. sessiliflora, C. longifolia, C. genistoides, C. intermedia, C. subternata and C. maculata), were determined to establish the variation between species. The results of the sensory study were used to create a honeybush sensory wheel and lexicon. The “characteristic” sensory profile of honeybush tea can be described as a combination of floral, sweet, fruity and plantlike flavours with a sweet taste and a slightly astringent mouthfeel. Sensory results indicated that the species could be divided into three distinct groups; group A (C. sessiliflora, C. intermedia and C. genistoides), group B (C. longifolia and C. subternata) and group C (C. maculata). Group A was associated with fynbos floral, fynbos sweet and plantlike attributes, group B with rose geranium and fruity sweet attributes and group C with woody, boiled syrup and cassia/cinnamon attributes. Gas chromatography-olfactometry analysis of the C. maculata aroma fraction indicated that the spicy note of its aroma could possibly be explained by the high concentration of the volatile component eugenol. However, none of the aroma impact volatiles had a specific cassia/cinnamon note. Large variation in the composition of the honeybush infusions was revealed through the quantification of the soluble solids, total polyphenol and individual monomeric polyphenolic compounds, as well as the absorbance (“colour”). Infusions of C. genistoides, C. longifolia and C. sessiliflora had the highest soluble solids and total polyphenol content, as well as the highest absorbance values. Only mangiferin, isomangiferin, hesperidin and compound C (unidentified compound) were detected in all six Cyclopia species. Cyclopia genistoides, C. longifolia and C. sessiliflora, in order of prominence, contained the highest concentration of both mangiferin and isomangiferin whereas C. genistoides and C. maculata contained the highest hesperidin content. The bitter taste present in certain Cyclopia species appeared to be due to a high mangiferin content, however, compounds such as isomangiferin and compound C might also have played a role. The effect of fermentation (oxidation) temperature (80°C and 90°C) and time (8 h, 16 h, 24 h and 32 h) of C. genistoides, C. subternata and C. maculata on the sensory characteristics of their infusions was also investigated. Fermentation for longer than 8 h resulted in an increase in positive sensory attributes and a decrease in negative sensory attributes rather than the formation of new sensory attributes. A fermentation temperature/time combination of 80°C/24 hours or 90°C/16 h was required for C. genistoides, C. subternata and C. maculata. Fermenting C. genistoides at 90°C would result in a honeybush infusion with slightly less rose geranium notes whereas C. subternata can be fermented at either 80°C or 90°C, depending on whether floral or apricot jam notes are desired. Cyclopia maculata should preferably not be fermented at 90°C due to an increase in negative sensory attributes (hay/dried grass and green grass). Fermentation reduced the soluble solids content, total polyphenol content, colour and concentration of individual polyphenolic compounds. Changes in the taste and mouthfeel of honeybush tea could be attributed to changes in the polyphenolic composition caused by the high temperature oxidation. Mangiferin associated with the bitter taste of C. genistoides, while in C. subternata astringency may be partly attributed to the mangiferin and isomangiferin content. The study substantiated the need for further research on the contribution of the major phenolic compounds towards the taste and mouthfeel of Cyclopia species. / AFRIKAANSE OPSOMMING: Die sensoriese profiel, fenoliese samestelling en kleur van heuningbostee, berei van ses Cyclopia spesies (C. sessiliflora, C. longifolia, C. genistoides, C. intermedia, C. subternata en C. maculata), is bepaal ten einde die mate van variasie vas te stel. Die resultate van die sensoriese studie is gebruik om 'n sensoriese wiel en leksikon vir heuningbostee te ontwikkel. Die “karakteristieke” sensoriese profiel van heuningbostee kan beskryf word as 'n kombinasie van blomagtig, soet, vrugtig en plantagtige geure met 'n soet smaak en 'n effense frankheid. Sensoriese resultate het aangedui dat die spesies in drie groepe verdeel kon word; groep A (C. sessiliflora, C. intermedia and C. genistoides), groep B (C. longifolia and C. subternata) en groep C (C. maculata). Groep A is met fynbos blom, fynbos-soet en plantagtige geure geassosieer, groep B met roos geranium en vrugtige-soet geure en group C met houtagtige, gekookte stroop en kassia/kaneel geure. Gaschromatografie-olfaktometrie analises van C. maculata se aroma fraksie het getoon dat die speseryagtige aroma moontlik as gevolg van die hoë konsentrasie van die vlugtige komponent, eugenol, kon wees. Geen van die aroma-impak vlugtige verbindings het egter 'n spesifieke kassia/kaneelagtige noot gehad nie. Groot variasie in die samestelling van heuningbostee ten opsigte van die inhoud van oplosbare vastestowwe, totale polifenole en monomeriese fenoliese verbindings, asook die absorbansie (“kleur”) is aangetoon. Heuningbostee berei van C. genistoides, C. longifolia en C. sessiliflora het die hoogste oplosbare vastestowwe en totale polifenol inhoud, asook die hoogste absorbansie waardes gehad. Slegs mangiferien, isomangiferien, hesperidien en verbinding C (ongeïdentifiseerde verbinding) is in al ses Cyclopia spesies geïdentifiseer. Cyclopia genistoides, C. longifolia en C. sessiliflora, in volgorde van belangrikheid, het die hoogste konsentrasie van beide mangiferien en isomangiferin gehad teenoor C. genistoides en C. maculata wat die hoogste hesperidien konsentrasie gehad het. Die bitter smaak teenwoordig in sekere Cyclopia spesies blyk moontlik as gevolg van die hoë mangiferien inhoud te wees, hoewel komponente soos isomangiferien en komponent C dalk ook 'n rol mag speel. Die effek van die fermentasie temperatuur (80°C en 90°C) en tyd (8 h, 16 h, 24 h en 32 h) van C. genistoides, C. subternata en C. maculata op die sensoriese eienskappe van heuningbostee is ondersoek. Fermentasie vir langer as 8 h het tot 'n toename in positiewe sensoriese eienskappe en afname in negatiewe sensoriese eienskappe gelei eerder as die ontstaan van nuwe sensoriese eienskappe. Om heuningbostee met 'n optimum sensoriese profiel te verkry is 'n fermentasie temperatuur/tyd kombinaise van 80°C/24 h of 90°C/16 h nodig vir C. genistoides, C. subternata en C. maculata. Cyclopia genistoides wat by 90°C gefermenteer word sal minder van die roos geranium note bevat, terwyl C. subternata by 80°C of 90°C gefermenteer kan word, afhangende of 'n blomagtige of 'n appelkooskonfyt noot verlang word. Fermentasie by 90°C word nie aanbeveel C. maculata nie as gevolg van die toename van sekere negatiewe sensoriese eienskappe (hooi/droe gras aroma en -geur en groen gras aroma). Fermentasie het die inhoud van oplosbare vastestowwe, totale polifenole, individuele polifenoliese verbindings, asook kleur verminder. Veranderinge in die smaak en mondgevoel van heuningbostee kon toegeskryf word aan die veranderinge in die polifenoliese inhoud as gevolg van die hoë temperatuur oksidasie. Mangiferien is met die bitter smaak van C. genistoides geassosieer, terwyl mangiferien and isomangiferien moontlik deels frankheid in C. subternata veroorsaak. Die studie het die noodsaaklikheid vir verdere navorsing op die bydrae van die hoof fenoliese verbindings tot die smaak en mondgevoel van Cyclopia spesies gestaaf.
3

Consumer Choice of Hotel Experiences: The Effects of Cognitive, Affective, and Sensory Attributes

Kim, Dohee 02 August 2011 (has links)
Understanding the choice behavior of customers is crucial for effective service management and marketing in the hospitality industry. The first purpose of this dissertation is to examine the differential effects that cognitive, affective, and sensory attributes have on consumer hotel choice. The second purpose is to examine the moderating effects of consumer choice context on the relationship between the cognitive, affective, and sensory attributes and hotel choice. To achieve these two purposes, this dissertation includes the design of a choice experiment to examine how cognitive, affective, and sensory attributes predict consumer hotel choice using multinomial logit (MNL) and random parameter (or mixed) logit (RPL) models. For choice experiments, the main objectives are to determine the choice attributes and attribute levels to be used for the choice modeling and to create an optimal choice design. I used a Bayesian D-optimal design for the choice experiment, which I assess from the DOE (design of experiment) procedure outlined in JMP 8.0. The primary analysis associated with discrete choice analysis is the log-likelihood ratio (LR) test and the estimation of the parameters (known as part-worth utilities), using LIMDEP 9.0. The results showed that the addition of affective and sensory attributes to the choice model better explained hotel choice compared to the model with only cognitive attributes. The second purpose is to examine the moderating effects of choice context on the relationship between cognitive, affective, and sensory attributes and hotel choice. Using a stated choice model, respondents were randomly divided into two different groups and asked to evaluate their preference for two differently manipulated choice sets. For this purpose, it is necessary to include interaction effects in the choice model. This study identified the differences among choice criteria based on two different contexts. Among eight interaction effects, four interaction effects with the contexts -- price, comfortable, room quality, and atmosphere -- were statistically significant on hotel choice. The findings provide hotel managers with important insights and implications in terms of target segmentation, product development, and marketing communication strategy. / Ph. D.
4

Seediness and Sensory Differences between Highbush, Southern Highbush, and Rabbiteye Blueberries

Pegg, Amanda Renee 15 August 2014 (has links)
Seediness and other differences between rabbiteye-RB (Vaccinium ashei), southern highbush-SHB (Vaccinium darrowii), and commercial market equivalent, highbush-HB (Vaccinium corymbosum) varieties/lines were determined. Forty six selections of rabbiteye and southern highbush blueberries, and three highbush varieties, were analyzed for seediness (seeds per berry volume, SPV). There were no differences (p > 0.05) in SPV between SHB and RB selections, but differences (p < 0.05) existed within species. Berries were assigned to 8 groups based on SPV to conduct sensory panels and chemical analysis. Consumers perceived RB more different than SHB from HB blueberries. In the descriptive panel, differences (p < 0.05) were found in shriveling, skin intactness, grittiness, seediness, and tartness. The soluble solids to acid ratio of HB, SHB, and RB averaged 16.05, 9.60, and 11.05%, respectively. Some consumers and trained panelists can discern differences due to seediness and other traits between blueberry species.
5

Development and characterisation of a functional beverage from red-fleshed Japanese plums (Prunus salicina L.)

Steyn, Naomi 03 1900 (has links)
Thesis (MSc Food Sc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Nectar formulations containing red-fleshed plum pulp and varying amounts of red-fleshed plum skin extract were developed. Red-fleshed plum nectar formulations containing 0, 8, 16, 24, and 32% skin extract were benchmarked against twenty-two commercial beverages containing red, violet and blue fruits. The total soluble solid content, pH, titratable acidity, colour, total polyphenolic, individual polyphenolic, total anthocyanin, and ascorbic acid contents, as well as antioxidant activity (oxygen radical antioxidant capacity (ORAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and ferric reducing/antioxidant power (FRAP)) of the commercial beverages and plum formulations were determined. The plum nectar formulations had similar or higher total polyphenolic content, antioxidant activity, and colour values than the average for the commercial beverages. The individual polyphenolic compounds analysed in the nectar formulations were cyanidin-3-glucoside, cyanidin-3- rutinoside, quercetin-3-glucoside, quercetin-3-rutinoside, quercetin-3-xyloside, and neochlorogenic acid. Increasing polyphenolic content and antioxidant activity was observed with an increase in skin extract content of the formulations. The sensory attributes of the formulations were plum and plantlike aroma, plum and plantlike flavour, sweetness, acidity, and astringency. Increases in plantlike aroma and flavour, acidity, and astringency in conjunction with decreases in plum aroma, plum flavour, and sweetness extract were observed with an increase in skin extract. Consumer analysis indicated that all formulations were acceptable. The 0 and 16% skin extract formulations were most preferred, while the 32% skin extract formulation was least preferred. A shelf-life study was conducted in two phases. In Phase 1, the 0, 16 and 24% skin extract formulations were stored at 0 and 5°C (analysis time points: before pasteurisation, after pasteurisation (week 0), and after 1, 2, 4, 6, 8, 12, 16, 18, 20, and 24 weeks of storage). Chemical analyses conducted included colour, total polyphenolic, individual polyphenolic compound, and total anthocyanin contents, and antioxidant activity (DPPH• scavenging activity). Results from Phase 1 indicated close associations between the 16 and 24% skin extract formulations, and between these formulations and all chemical attributes. Regression analysis of results indicated significant (P 0.05) decreases in red colour, total anthocyanins, cyanidin-3-glucoside, cyanidin-3- rutinoside, DPPH• scavenging activity, total polyphenolic content, quercetin-3-rutinoside, and quercetin- 3-xyloside for formulations stored at 0°C. The total and red colour, total anthocyanins, cyanidin-3- glucoside, and cyanidin-3-rutinoside in formulations stored at 5°C showed similar results. During Phase 2 of the shelf life study, sensory analysis was conducted on the 0 and 24% skin extract formulations stored at 5°C (preparation time points: 0, 1, 2, and 3 months). Sensory attributes, including plum, plantlike, and raisin flavour, sweetness, acidity, and astringency, were stable during storage. Chemical results from Phase 2 were similar to those of Phase 1. The chemical and sensory stability of formulations after 24 weeks of storage in Phase 1 and Phase 2 indicated that, with the exception of the anthocyanin degradation, the formulations could be beneficial to juice industries. Thus, red-fleshed plum nectars have the potential to compete with high-antioxidant fruit beverages. / AFRIKAANSE OPSOMMING: Nektarformulasies wat rooivleis pruimpulp en varieërende hoeveelhede rooivleis pruimskilekstrak bevat, is ontwikkel en ondersoek. Rooivleis pruimnektarformulasies wat 0, 8, 16, 24, en 32% skilekstrak bevat, is vergelyk met twee-en-twintig kommersiële drankies wat rooi, violet en blou vrugte bevat. Die totale oplosbare vastestof, totale polifenoliese, individuele polifenoliese, totale antosianien- en askorbiensuur inhoude, sowel as die pH, titreerbare suurheid, kleur, antioksidant aktiwiteit (suurstofradikale antioksidantkapasiteit (ORAC), 2,2-difeniel-1-pikrielhidrasiel (DPPH) radikaal blussingsaktiwiteit, en ysterreduserende/antikoksidantkrag (FRAP)) van die kommersiële drankies en pruimnektarformulasies, is bepaal. Die pruimnektarformulasies het soortgelyke of hoër totale polifenoliese inhoud, antioksidantaktiwiteit, en kleurwaardes gehad in vergelyking met die gemiddelde vir die kommersiële drankies. Die individuele polifenoliese verbindings wat in die nektarformulasies geanaliseer is, was sianidien-3-glukosied, sianidien-3-rutinosied, kwersetien-3-glukosied, kwersetien-3-rutinosied, kwersetien-3-xylosied, en neochlorogeniese suur. ‘n Toenames in die kleurwaardes, polifenoliese inhoud, en antioksidantaktiwiteit is waargeneem met ‘n toename in skilekstrak is in die formulasies. Die sensoriese eienskappe van die formulasies was pruim- en plantagtige aroma, pruim- en plantagtige geur, soetheid, suurheid, en frankheid. Toenames in plantagtige aroma en geur, suurheid en frankheid, sowel as ‘n afname in pruimaroma, pruimgeur, en -soetheid, is met ‘n toename in skilekstrak waargeneem. Verbruikersanalise het aangedui dat al die formulasies aanvaarbaar was. Die 0 en 16% skilekstrakformulasies was die mees aanvaarbaarste, terwyl die 32% skilekstrakformulasie die minste aanvaarbaar geag is. ‘n Rakleeftydstudie is in twee fases gedoen. In Fase 1 is die 0, 16, en 24% skilekstrakformulasies by 0 en 5°C gestoor (analiseringstydpunte: voor pasturisasie, na pasturisasie (week 0), en na 1, 2, 4, 6, 8, 12, 16, 18, 20, en 24 weke van berging). Chemiese analise wat gedoen is, sluit totale polifenoliese, individuele polifenoliese verbinding, en totale antosianien inhoude, sowel as kleur en antioksidantaktiwiteit (DPPH• blussingsaktiwiteit) in. Resultate van Fase 1 het ‘n nou verband tussen die 16 en 24% skilekstrakformulasies, sowel as tussen hierdie formulasies en hul chemiese kenmerke aangedui. Regressie-analise van resultate het betekenisvolle (P 0.05) afnames geïllustreer in rooi kleurwaardes, DPPH• blussingsaktiwiteit, sowel as totale antosianiene, sianidien-3-glukosied, sianidien-3-rutinosied, totale polifenoliese, kwersetien-3-rutinosied, en kwersetien-3-xylosied inhoude van die formulasies wat by 0°C gestoor is. Die totale kleur-, rooi kleurwaardes, sowel as totale antosianien, sianidien-3-glukosied, en sianidien-3-rutinosied in die formulasies wat by 5°C gestoor is, het soortgelyke resultate gegee. Gedurend Fase 2 van die rakleeftydstudie is sensoriese analise op die 0 en 24% skilekstrakformulasies wat by 5°C gestoor is, gedoen (voorbereidingstydpunte: 0, 1, 2, en 3 maande). Sensoriese eienskappe, insluitend pruim-, plantagtige-, en rosyntjiesmake, soetheid, suurheid, en frankheid, was stabiel gedurende berging. Chemiese resultate van Fase 2 was soortgelyk aan dié van Fase 1. Die chemiese en sensoriese stabiliteit van die formulasies na 24 weke van opberging in Fase 1 en Fase 2 nieteenstaande antosianienafname, het aangedui dat die formulasies voordelig kan wees vir die vrugtedrankiebedryf. Dus het rooivleis pruimnektars die vermoeë om met hoë antioksidant vrugtedrankies mee te ding.
6

CHARACTERIZATION OF DRY-AGED MEAT FLAVOR PRECURSORS AND LIBERATION MECHANISM THROUGH A METABOLOMICS APPROACH

Derico Setyabrata (11791949) 20 December 2021 (has links)
<p>Within the last decade, the popularity and interest in dry-aging have constantly increased among both consumers and producers. Dry-aging is a natural value-adding process where meat is exposed to a controlled refrigerated environment without any protective barrier during the aging process. This process leads to the development of unique flavors in the final meat product. Although the prevalence of this process is increasing, there are inconsistent reports regarding the impacts of dry-aging on meat sensory attributes, especially on the flavor aspect. Given that flavor generation is dependent on the composition and availability of flavor precursors, the presence or absence of these precursors may contribute to the inconsistency observed. Thus the main objective of the research described here was to characterize the flavor precursors in dry-aged meat and elucidate potential factors or mechanisms favoring to their production.</p> <p> To achieve this objective, metabolomics analysis was conducted in conjunction with various chemical analyses (free amino acids, fatty acids, sugar content and volatile analysis), microbiome profiling and meat quality analysis (tenderness, water holding capacity, color stability, oxidative stability, microbial attributes and sensory analysis) to identify the essential flavor precursors and their production process. In addition, similar analyses were conducted using multiple meat sources (grass-fed beef loins, cull cow beef loins and pork loins) aged by wet-aging (WA), conventional dry-aging (DA), dry-aging in bag (DWA) and UV-light dry-aging (UDA) to elucidate the impact of the different aging treatments on meat quality, sensory attributes and flavor precursor availability.</p> <p>Regardless of the meat source, the results demonstrated that dry-aging altered the meat flavor precursor compositions, primarily by increasing the presence of protein-derived precursors (e.g., free amino acids and dipeptides), especially glutamine and glutamate compounds. Additionally, nucleotide and carbohydrate-derived compounds such as adenosine and reducing sugars were greatly increased after the dry-aging process. While the fatty acid profile was minimally affected, metabolomics analysis revealed a decrease in sterol and terpenoid lipids following dry-aging, which could potentially reduce off-flavors development in the meat. Other compounds such as vitamin B and vitamin C were also detected in the dry-aged product, which potentially could contribute to the flavor development.</p> <p>Analysis of the liberation mechanisms demonstrated that dehydration played a role in increasing the concentration of the flavor precursors in the dry-aged product, potentially promoting greater (e.g., Maillard reaction) during cooking. Furthermore, microorganisms might be responsible for further increasing the availability of flavor precursors in dry-aged meat, especially free amino acids, along with the dehydration process. Microbiome profiling found that <i>Pseudomonas</i> spp. are the most prominent bacterial species in microbial communities found on dry-aged meat which could affect the precursor release in dry-aged meat. Metabolomics analysis also indicated increased glutathione metabolism during dry-aging, which could lead to the liberation of glutamine-related compounds. The analysis also identified other compounds such as porphyrin rings (iron-related) and shikimic acid (bacterial metabolism), providing further examples of how metabolomics can identify dry-aged flavor precursors and reveal other potential mechanisms related to flavor development mechanisms.</p> <p>These outcomes demonstrate that dry-aging alters meat flavor precursor composition, mainly by increasing the availability of protein-, nucleotide- and carbohydrate-derived compounds. Such results indicate that the Maillard reaction is likely be the main mechanism in flavor generation in dry-aged meat. The current results provided more insights into the dry-aging flavor development, especially highlighting important flavor precursor such as glutamate and glutamine containing products, likely to contribute to the dry-aged flavor. Future study to identify the impact of different microorganism (especially mold and yeast) on dry-aging flavor development would be of interest. Additionally, impact of different cooking process should also be studies to maximize the dry-aged flavor potential from the product.</p>
7

Microstructure and sensory attributes of rabbiteye blueberries subject to osmotic dehydration and two freezing methods

Garcia, Antonio Carlos 09 December 2022 (has links)
Frozen, thawed and osmotically-dehydrated highbush (HB) (Vaccinium corymbosum) and rabbiteye (RB) (V. virgatum) blueberries were analyzed under a scanning electron microscope (SEM) to observe microstructural differences in their skin. Rabbiteye blueberries of both frozen, thawed and osmotically-dehydrated treatments, had thicker skins than highbush blueberries. Rabbiteye blueberries, collected from local farms, packed and blast frozen (PBF), had thinner skins than individually quick-frozen (IQF) blueberries. Washing berries prior to freezing had no effect on skin thickness. Sensory analysis of samples determined there were no differences (p > 0.05) between PBF and IQF methods and species with respect to skin intactness, grittiness, sweetness, and blueberry flavor. IQF berries obtained from one farm had tougher skin (p ≤ 0.05) than other berries regardless of treatment. RB were rated lower in juiciness and higher in grittiness than HB berries whereas LH berries were rated lower in shriveling and higher in skin intactness.
8

The application of food-grade chitosan and another food-grade compound in coatings to control Tyrophagus putrescentiae (Schrank, Family: Acaridae) growth on dry-cured hams and their impact on dry-cured ham quality

Shao, Wenjie 11 May 2022 (has links)
The objective of this research was to evaluate if chitosan and another food-grade compound can be incorporated into food-grade coatings in conjunction with propylene glycol and polysaccharides to control Tyrophagus putrescentiae growth without affecting sensory attributes, water activity, and moisture content of dry-cured hams. Each coating solution was coated on ham cubes (2.5 × 2.5 × 2.5 cm3, n = 5/treatment) or infused in ham nets, and dry-cured ham cubes were wrapped in the ham nets prior to inoculation with 20 mixed-sex adult mites. Randomized complete block designs with two replications were utilized to evaluate the efficacy of treatments at controlling mite growth on dry-cured ham cubes. When CH was mixed with XG and infused into a net, fewer mites (15.7 and 21.0 mites) were on ham cubes (P < 0.05) in comparison to the control (211.2 mites). Results indicated that CH contributed to controlling mite growth since 1% XG alone did not control mite growth. Difference from control test results indicated that no sensory differences existed (NS) between CH-treated and control ham slices. The addition of a food-grade compound (SP or 24P) to the XG coatings enhanced mite control efficacy. When 1% SP was added to 1% XG, it effectively controlled mite growth in both coating and netting treatments. Increasing 1% SP to 2% SP did not significantly (NS) control mite growth in the coating solution but did control mite growth when infused in the net. Both coating and netting treatments with 2% 24P + 1% XG controlled mite growth. When 24P was the only ingredient in the treatment, both 1% and 2% 24P controlled mites when infused in the net. The addition of SP did not (NS) impact the sensory attributes of the dry-cured ham. The 2% 24P + 1% XG treatment differed in moistness (P < 0.05) when compared to the blind control, but the rating was still less than 2 (moderately different). Overall, results from these studies indicate that chitosan can potentially be added in coatings or ham nets as tools to control mites in an integrated pest management program for dry-cured hams.
9

Efeito do teor de fibra e do processamento de milho na qualidade e perfil de ácidos graxos da carne de bovinos Nelore / Effect of roughage level and corn processing on meat quality and fatty acid profile of Nellore bulls

Rizzo, Pâmela Marcos 27 February 2013 (has links)
Foi avaliado o efeito do método de processamento do milho (PRC) e do teor de fibra insolúvel em detergente neutro proveniente de forragem (FDNf) na qualidade físico- químicas, analise sensorial e no perfil de ácidos graxos da carne in natura e após cocção de bovinos Nelore em confinamento. Foram utilizados 56 bovinos não castrados da raça Nelore, com peso inicial de 382 kg. Os animais foram distribuídos em baias individuais sendo separados de acordo com o peso vivo inicial, formando assim o delineamento em blocos completos casualizados, em esquema fatorial 2x4. Do total de 112 animais foram selecionados aleatoriamente 56 bovinos perfazendo sete animais de cada tratamento. Foram confinados durante 81 dias, sendo 21 dias de adaptação e 60 dias de tratamento. As dietas de tratamento continham teores de 3, 8, 13 e 18% de fibra insolúvel em detergente neutro proveniente de forragem (FDNf) e dois métodos de processamentos dos grãos de milho, sendo grão úmido ensilado - GU e grão seco moído fino - MM. Os dados foram analisados pelo procedimento MIXED e as medias foram determinadas pelo LSMEANS. As medias foram determinadas pelo LSMEANS. Testes para os efeitos fixos com valores de probabilidade inferiores ou iguais a 0,05 foram considerados significativos. Não foi observado efeito de interação entre FDNf e PRC para as características de qualidade da carne como umidade, força de cisalhamento, pH, cor e características sensoriais. Ao avaliar o teor de EE do músculo Longissimus dorsi houve diferença (P=0,05) entre os métodos de PRC utilizados. Os valores de EE obtidos no músculo L. dorsi dos animais alimentados foram de 1,80 vs. 1,48 para GU e MM, respectivamente. A relação ?6:?3 apresentou decréscimo linear com o aumento no teor de FDNf, mostrando uma relação de 4,24 na dieta com 3% e 3,31 para as dietas contendo 18% de FDNf (P<0,05). A concentração de CLA encontrada na carne de animais alimentados com GU está dentro da faixa recomendada para carne bovina que é de 0,2 a 1,0% do total de ácidos graxos. Houve um aumento no teor de lipídios na carne dos animais que receberam dietas com milho grão úmido ensilado. O aumento no teor de FDNf na dieta resultou em menor relação ?6:?3 na carne, algo desejável sob o ponto de vista da saúde do consumidor. O cozimento da carne não alterou o perfil de ácidos graxos da carne, pode-se então estimar o perfil de ácidos graxos por meio da análise em carnes cruas. / Was evaluated the effect of corn processing method (PRC) and the content of neutral detergent fiber from roughage (NDF) in physicochemical quality and sensory analysis in the fatty acid profile of fresh beef and after cooking of Nelore cattle feedlot. We used 56 Nellore bulls with an initial weight of 382 kg. The animals were divided into individual stalls being separated according to initial body weight, thus forming the randomized complete block design in a 2x4 factorial design. Of the total of 112 animals were randomly selected 56 bulls totaling seven animals of each treatment. Were confined for 81 days, being 21 days of adaptation and 60 days of treatment. The treatment diets contained levels of 3, 8, 13 and 18% neutral detergent fiber from roughage (NDFr) and two methods of processing corn grains, being high moisture corn - GU and finely ground dry corn - MM. The data were analyzed using the MIXED procedure and the media were determined by LSMEANS. Tests for fixed effects with probability values less than or equal to 0.05 were considered significant.] There was no interaction effect between NDFr and PRC for meat quality characteristics such as moisture, shear force, pH, color and sensory characteristics. When evaluating the EE content of the Longissimus dorsis there was difference (P=0.05) between the PRC methods used. The EE values obtained in the animals L. dorsi muscle were 1.80 vs. 1.48 for GU and MM, respectively. The concentration of CLA found in animals meat fed with GU is within the recommended range for beef which is 0.2 to 1.0% of total fatty acids. The relationship ?6:?3 displayed a linear decrease with the increase of NDFr level, showing a ratio of 4.24 in the diet with 3% NDFr and 3.31 in diets containing 18% NDFr (P<0.05). The concentration of CLA found in animals meat fed with GU is within the recommended range for beef which is 0.2 to 1.0% of total fatty acids. There was an increase in fat content in the meat of animals fed diets with high moisture corn silage. The increase in the content of FNDr in the diet, resulted in a lower ratio of ?6: ?3 in the flesh, desirable from the point of view of consumer health. The cooking of the meat did not alter the fatty acid profile of meat, can then estimate the fatty acid profile by analyzing in raw meats.
10

Análise físico-química, microbiológica e sensorial de cultivares de feijão / Physical-chemical, microbiological and sensorial analysis of common bean cultivars

Oliveira, Viviani Ruffo de 05 February 2009 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objectives of this work were: (1) to evaluate the nutritional and microbiological quality of common beans (Phaseolus vulgaris L.) processed with or without soaking water; (2) to analyze the sensorial traits of common bean cultivars and to compare the efficiency of quantitative descriptive analysis with not-trained and trained people; (3) to investigate the sensorial traits of common bean cultivars and to compare the efficiency of quantitative descriptive analysis with not-trained and trained people;(4) to evaluate the effect of storage under refrigeration during six months on the cooking quality, the content of minerals and the darkness of common bean cultivars with black and color tegument. Grains of Iraí and BRS Expedito beans cultivars were submitted to soaking in distilled water for eight hours, at environmental temperature. The cooking was made with the use or discard of soaking water. The minerals were determined in the grains and in the broth separately, and the microorganisms, in the mixture of grains and broth. The sensorial analysis was carried with grains of four common bean cultivars: BRS Expedito, BRS Campeiro, Iraí and Carioca. Each common bean sample was macerated for eight hours and the water was separated of the grains and placed under firing in pressure pan. The not-trained and trained people received 25 g of the four cooked cultivars and the analysis was taken using an evaluation file following the technique of Quantitative Descriptive Analysis. To evaluate the cooking time, it was used four cultivars of beans: BRS Expedito, BRS Campeiro, Pérola and Carioca and the cooking was carried through in a domestic pressure pan during 15, 20, 25 or 30 minutes. The sensorial analysis was effected in two stages: training for Qualitative Descriptive Analysis and the sensorial analysis properly, with seven trained panel. It was used six cultivars (Macanudo, Guapo Brilhante, BRS Campeiro, Pérola, Carioca and LH 5) and three times of storage (0, 3 and 6 months). It was evaluated the cooking quality (water absorption, normal and hard grains and cooking time), the mineral content and the grain clarity ( L value). According to the results, minerals composition in the grains and in the bean broth were not modified by the discarding maceration water. The bean broth presented high amount of potassium, magnesium and sulphur content. The discard of the soaking water did not improve microbiological quality of the processed common bean. Iraí and BRS Expedito cultivars may be cooked with the use or discard of soaking water because minerals content and microbiological quality of the processed common bean are maintained. The sensorial attributes texture and bean broth were evaluated with the highest experimental precision to the trained people, because lesser coefficient of variation and error mean squares were observed. The not-trained people discriminate greater number of sensorial attributes in common bean cultivars, but with a reduced amount of experimental precision. The trained group recognizes differences in the texture and broth the beans, with highest experimental precision. The panel recognized differences among the cultivars such as: uniformity tegument color, hardness, graininess, broth color and viscosity. The rupture of the tegument of the grains was bigger as it was increased the cooking time. The hardness and the graininess received best notes as longer as the cooking time of the common bean. The use of 20 the 25 minutes to cook in domestic pressure pan seems to identify black and carioca cultivars of common bean with the best evaluation profile, besides keeping the integrity of the cooked grains. Beans storage for six months reduces the grains capacity of water absorption and influences negatively in the darkness of Carioca group. However, it does not increase the amount of hardshell grains and the cooking time, as well as the minerals content of the grains. / Os objetivos desse trabalho foram: (1) analisar se o processamento do feijão deve ser realizado com o aproveitamento ou não da água de maceração, visando à manutenção da qualidade nutricional e microbiológica; (2) avaliar o perfil sensorial de cultivares de feijão e comparar a eficiência da técnica de análise descritiva quantitativa com avaliadores nãotreinados e treinados; (3) investigar o tempo de cozimento que deverá ser utilizado, em panela de pressão doméstica, para a identificação de cultivares de feijão de grãos preto e carioca com atributos sensoriais de melhor perfil para o consumo; (4) avaliar o efeito do armazenamento sob refrigeração (temperatura de 0 ºC e umidade relativa do ar de 50%) ao longo de seis meses sobre a qualidade para o cozimento, o teor de minerais e a claridade dos grãos de feijão de cultivares de tegumento preto e de cor. Grãos das cultivares de feijão Iraí e BRS Expedito foram submetidos à embebição em água destilada por oito horas, à temperatura ambiente. O cozimento foi realizado com e sem o aproveitamento da água de maceração. Os minerais foram determinados nos grãos e no caldo, separadamente, e os microrganismos, na mistura de grãos e caldo. Para a avaliação do perfil sensorial, grãos de quatro cultivares de feijão: (BRS Expedito, BRS Campeiro, Iraí e Carioca) foram submetidos à análise sensorial por avaliadores treinados e não-treinados. As amostras de feijão, de cada cultivar, foram maceradas por oito horas e colocadas sob cocção em panela de pressão. Os avaliadores não treinados e os treinados receberam 25 g de feijão cozido, de cada uma das quatro cultivares. A análise foi realizada com o auxílio de uma ficha de avaliação e utilizou-se a técnica da 14 Análise Descritiva Quantitativa (ADQ). Para se avaliar o tempo de cozimento, utilizaram-se grãos de quatro cultivares de feijão: BRS Expedito, BRS Campeiro, Pérola e Carioca, os quais foram submetidos ao cozimento em panela de pressão doméstica por 15, 20, 25 ou 30 minutos e em seguida realizou-se uma análise sensorial com avaliadores treinados. Seis cultivares (Macanudo, Guapo Brilhante, BRS Campeiro, Pérola, Carioca e LH 5) e três tempos de armazenamento dos grãos (0, 3 e 6 meses) foram avaliados quanto à qualidade para o cozimento (absorção de água, grãos normais, grãos hardshell e tempo de cozimento), o teor de minerais e a coloração dos grãos (valor de L ). Os resultados obtidos evidenciaram que a composição de minerais nos grãos e no caldo de feijão não foi alterada pelo descarte da água de maceração para o cozimento. O caldo de feijão apresentou altos teores de fósforo, potássio, magnésio e enxofre. A eliminação da água de maceração não melhorou a qualidade microbiológica do feijão processado. O cozimento das cultivares de feijão Iraí e BRS Expedito pode ser realizado com o aproveitamento ou com o descarte da água de maceração, pois há manutenção do teor de minerais e da qualidade microbiológica do feijão. Em relação ao perfil sensorial, os avaliadores reconheceram diferenças para as cultivares de feijão quanto à uniformidade da cor do tegumento, à dureza, à granulosidade, à cor do caldo e à viscosidade. Os atributos sensoriais textura e caldo foram avaliados com maior precisão experimental pelos avaliadores treinados, enquanto que os avaliadores não-treinados diferenciaram maior número de atributos sensoriais nas cultivares de feijão, mas com menor precisão experimental. Em relação aos diferentes tempos de cocção observou-se que a ruptura no tegumento dos grãos foi maior à medida que se aumentou o tempo de cozimento. A dureza e a granulosidade receberam melhores notas quanto maior foi o tempo de cozimento dos grãos de feijão. A utilização de 20 a 25 minutos de cozimento em panela de pressão doméstica possibilita a identificação de cultivares de feijão de grãos preto e carioca com o melhor perfil para o consumo, mantendo a integridade dos grãos cozidos. O armazenamento de feijão por seis meses reduz a capacidade de absorção de água de algumas cultivares e influencia negativamente na claridade dos grãos do tipo Carioca. Entretanto, não aumenta a porcentagem de grãos hardshell e o tempo de cozimento, além disso, não altera o teor de minerais dos grãos avaliados após seis meses de armazenamento.

Page generated in 0.0514 seconds