Polymorphic crystal forms in food fats contribute to physical characteristics of the fats and consequently to their performance in fat based foods. In the present study the phase transitions associated with polymorphism behavior of common food fats were investigated. The polymorphism of butters, margarines, cocoa butter and cocoa butter products were determined and the effects of certain ingredients and conditions of temperature were studied. The following polymorphic forms were detected: sub-alpha, alpha, beta' , beta'3, beta' 2, beta, beta2, and beta1; however, not all forms were observed in all fats. Margarines contained beta' and beta forms depending on their fat constituents, while butter, cocoa butter, and fat blends consisted of alpha, beta' and beta; only the beta' form of butter showed a sharp melting point. Rapeseed oil exhibited alpha, beta1 and beta 2 forms, depending on the degree of hydrogenation. / DSC measurements of fat blends were correlated with viscosity index measurements from Universal Material Testing Machine (UMTM) using a single cycle, back extrusion technique. A correlation of R2 = 0.70 (p = 0.95) was obtained. Viscosity index decreased as temperature increased, suggesting a possible relationship between viscosity index and solid fat fraction. This suggests that viscosity index could be a potential indicator of food fat textural properties which are evaluated by DSC. (Abstract shortened by UMI.)

Fresh-cut watermelon is appreciated for its taste, flavor, and juiciness. However, there are challenges in maintaining the freshness since fresh-cut processing of fruits promotes faster deterioration. Our objective was to determine the effectiveness of multilayered antimicrobial edible coating on the shelf-life of fresh-cut watermelon while keeping its original attributes for longer, without affecting its sensory properties. A set of solutions containing sodium alginate (0.5, 1, 2% w/w), beta-cyclodextrin, trans-cinnamaldehyde (antimicrobial agent), pectin, and calcium lactate were used as coating systems for fresh-cut watermelon cylinders. The samples were coated by the layer-by-layer dipping technique and stored at 4 degrees C for 15 days. Results were analyzed individually for each quality attribute evaluated, and the best concentration among the solutions to improve each attribute was found. Watermelon quality was measured in terms of texture, color, juice leakage (weight loss), oBrix, and pH. Microbiological analysis consisted of total coliforms, yeasts and molds, aerobics, and psychrotrophs. A consumer test was carried out (~ 40 panelists) to support the objective quality data. Panelists scored the samples using a 9-point hedonic scale. Uncoated samples served as controls. Quality tests were conducted at days 1, 3, 7, 12, and 15 of storage. Sensory tests showed high acceptance (P < 0.05) of the coated samples when compared to the controls. Quality attributes, particularly texture (firmness) and juice leakage (weight loss) were enhanced (P < 0.05) by the coating. Microbiological analysis demonstrated that alginate-based edible coating has a huge effect against microbial growth. 1% sodium alginate coating provided better preservation in terms of quality parameters, microbiological growth, and sensory acceptance. These results indicate that different ratios between solutions present a significant variation for each quality attribute measured in this study; and the thickness of the coating as well as the amount of antimicrobial are critical for shelf-life extension of fresh-cut watermelon. Hence, application of an alginate based multilayered edible coating has tremendous potential to enhance microbial quality and extend the shelf-life of fresh-cut watermelon.

This thesis investigates whether fats, akin to other taste stimuli, exhibit sensory properties such as mixture interactions. In order to determine gustatory, rather than tactile or olfactory effects, viscosity-controlled emulsions of deodorised oils were used as the base to which taste stimuli were incorporated and presented to a panel of trained assessors. In preliminary qualitative assessments, panellists described the 10% olive oil emulsion as saltier, stronger, fattier and having a more lingering aftertaste than the non-oil control, suggesting that oil modulates taste duration as well influencing taste intensity and/or perceived quality. Panellists were unable to rate the oil/fat taste per se with any degree of certainty hence further experiments examined the effect of oil on the perception of taste mixtures. In mixture interaction experiments, the addition of oil did not result in mixture suppression or enhancement for sweet, salty, sour or bitter while it significantly enhanced umami. To determine the locus of interaction, when MSG and oil were presented to each side of the tongue separately, the enhancement effect disappeared indicating a peripheral mechanism of interaction, similar to the attenuation of chilli burn by oil. In contrast, suprathreshold sucrose sweetness was enhanced by the contralateral presentation of oil, indicating sensory processing at a higher locus. Furthermore, the addition of oil significantly reduced bitterness in a caffeine-MSG mixture. Since earlier experiments did not indicate any interaction between oil and bitterness, the decrease in the perceived bitterness of this binary mixture is attributed to an increase in umami which is likely to have suppressed bitterness, the perceptually dominant component in this mixture. These findings suggest a gustatory role for fats in modulating the taste profile of mixtures, in particular, enhancing total taste intensity, prolonging taste duration, and enhancing umami. A taste receptor-based model of fat perception provides for an orosensory mechanism capable of signalling the arrival of the most energy-dense nutrient, essential fatty acids and fat-soluble vitamins. The chemosensory signal may also be the basis for hedonic responses with subsequent implications for intake.

Thesis (M.Sc.(Plant Production and Soil Science))--University of Pretoria, 2007. / Abstract in English. Includes bibliographical references (leaves 179 - 194).

Thesis (Ph. D.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains viii, 103 p. : ill. (some col.), maps. Vita. Includes abstract. Includes bibliographical references (p. 81-83).

Thesis (M. Phil.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 208-219).

Thesis (MSc Food Sc )--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The oxidative stability of crude, cold-pressed mango kernel fat (MKF) was determined over a period of 240 days using the peroxide value (PV), conjugated diene value (CD) and p-anisidine value (AV) tests. The changes in fatty acid profile were monitored with gas chromatography and the oxidative status of MKF effectively predicted by FT-NIR spectroscopy. Results obtained from the different methods complemented each other and indicated the stable character of mango kernel fat against oxidative deterioration. The fatty acid profile constituted palmitic acid (CI6:0; 8.43%), stearic acid (CI8:0; 34.98%), oleic acid (CI8:1 cis; 48.05%), linoleic acid (CI8:2; 6.60%) and arachidic acid (C20:0; 1.73%). Trace amounts of C16:1 (0.56%), C18:1 trans (0.25%), C18:3 (0.43%), C20:1 (0.25%) and C22:0 (0.40%) were also found. The freshly pressed MKF had a peroxide value of 2.7 meq.kg", CD value of 0.07% and an AV of 2.2 mmol.kg", After 40 days of storage, the peroxide values of MKF stored with and without exposure to a limited amount of oxygen at 5, 15,25 and 40°C increased to 5 meq.kg" and 4 meq.kg" respectively. Emulsification of MKF had a stabilising effect (maximum PV = 2.8 meq.kg'), while exposure to UV light had a catalysing effect (maximum PV = 5 meq.kg'). These maximum values, decreased after 40 days. The CD values of MKF samples stored with and without exposure to oxygen at 5, 15,25 and 40°C increased to 0.18% and 0.16%, respectively at day 40. The CD values of samples exposed to light increased to 0_20% and the emulsified samples showed similar values to that of the MKF samples not exposed to oxygen. The conjugated diene values remained stable after day 40. The p-anisidine values of the MKF samples both stored with and without exposure to oxygen at 5, 15, 25 and 40°C varied between 0.5 and 5 mmol.kg". The weak correlation to the measurement of nonanal, as well as the low levels of 2-alkenals produced by the MKF, resulted in these low and sometimes non-linear values. The peroxide, conjugated diene and p-anisidine values obtained for MKF stored at 25°C over 240 days were low due to the low content of polyunsaturated fatty acids in MKF. This compared favourably with the higher values attained for sunflower, canola and olive oil, which are all rich in polyunsaturated fatty acids. The minimal changes observed in the fatty acid profile of mango kernel fat indicated the stability of the saturated fatty acids (CI6:0 and CI8:0) and oleic acid. In addition, the instability of linoleic and linolenic acids was evident due to oxidative deterioration. A decrease of 7.41% and 12.80% was observed between day 0 and 240 for the C18:2/C16:0 and C18:2/C18:0 ratios respectively. The prediction of the oxidative status of the MKF samples by near infrared spectroscopy were possible after the development of calibration models from a total data set of 300 samples of which one-third was used for independent validation. Principle component analysis (PCA) indicated classification at 0, 40 and the remaining (80 - 240) days. The best calibration model for PV yielded a SEP (standard error of prediction) of 0.46 meq.kg", correlation coefficient (r) of 0.95, bias of 0.02 and a root mean square error of prediction (RMSEP) of 0.46 meq.kg". The CD calibration model had a correlation coefficient of 0.89, SEP of 0.01 %, bias of 0.001 and RMSEP of 0.01% when developed on a data set with no pre-processing applied. The AV calibration had a SEP of 0.32 mmol.kg", bias of 0.03, RMSEP of 0.32 mmol.kg" and rof 0.93. The C18:2 and C18:3 models were built using partial least squares (PLS) regression and the values obtained for SEP were 0.31% and 0.054%, RMSEP 0.32% and 0.05%, bias 0.05 and 0.01 and correlation coefficcients were 0.82 and 0.54 respectively. The calibrations for CI8:1, C18:0 and C16:0 yielded weaker correlations. Good correlations were obtained when calibrating the CI8:2/CI6:0 and C18:2/CI8:0 ratios. / AFRIKAANSE OPSOMMING: Die oksidatiewe stabiliteit van ru, koud-geperste mango kern vet (MKV) (Mangifera indica L.) is oor 'n periode van 240 dae bepaal deur gebruik te maak van die peroksiedwaarde (PV), gekonjugeerde dieen waarde (CD) en p-anisidien waarde (AV) toetse. Die veranderinge in die vetsuurprofiel is gemonitor deur gaschromatografie en die oksidatiewe status van MKV is akkuraat voorspel word deur Fourier transformasie naby infrarooi (FT-NIR) spektroskopie. Die resultate van die verskillende toetsmetodes komplementeer mekaar goed en dui die stabiliteit van mango kern vet teen oksidatiewe verval aan. Die vetsuurprofiel is saamgestel uit palimitiensuur (C16:0; 8.43%), steariensuur (C18:0; 34.98%), oleïensuur (C18:1 cis; 48.05%), linoleïensuur (C18:2; 6.60%) en aragiedsuur (20:0; 1.73%). Spoorhoeveelhede C16:1 (0.56%), C18:1 trans (0.25%), C18:3 (0.43%), C20:1 (0.25%) en C22:0 (0.40%) is ook geïdentifiseer. Die vars geperste MKF het 'n peroksiedwaarde van 2.7 meq.kg", 'n CD waarde van 0.07% en 'n AV waarde van 2.2 mmol.kg" getoon. Na afloop van 40 dae opbergingsperiode by 5, 15, 25 en 40°C het die PV van MKV met 'n beperkte blootstelling aan suurstof na 5 meq.kg" vermeerder, terwyl die waardes van monsters sonder suurstofblootstelling na 4 meq.kg" vermeerder het. Emulsifisering van MKV het 'n stabiliserende effek (maksimum PV = 2.8 meq.kg") terwyl blootstelling aan ultraviolet (UV) lig 'n kataliserende effek (maksimum PV = meq.kgl ) op oksidasie gehad het. Hierdie maksimum waardes het na 40 dae afgeneem. Die CD waardes van MKF monsters opgeberg by 5, 15, 25 en 40°C en met beperkte blootstelling aan suurstof het vermeerder tot 0.18% terwyl die monsters sonder suurstofblootstelling by bogenoemde temperature vermeerder het tot 0.16% na 40 dae. Die gekonjugeerde dieen waardes van die monsters blootgestel aan UV lig het vermeerder tot 0.20%; terwyl die geëmulsifiseerde monsters waardes soortgelyk aan die MKV monsters sonder blootstelling aan suurstof getoon het. Gekonjugeerde dieen waardes het gestabiliseer vanaf dag 40. Die p-anisidienwaardes van MKV monsters opgeberg by temperature van 5,15, 25 en 40°C, met en sonder blootstelling aan suurstof, het varieer tussen 0.5 en 5 mmol.kg". Die swak korrellasie tussen nonanal produksie en p-anisidienwaardes, sowel as die klein hoeveelhede 2-alkenale geproduseer, was verantwoordelik vir hierdie lae en nie linêere waardes. Die peroksied, gekonjugeerde dieen en p-anisidienwaardes wat verkry is nadat MKV by 25°C in 240 opgeberg is, was laag weens die klein persentasie poli-onversadigde vetsure teenwoordig in die vet. Dit vergelyk goed met die hoë waardes wat verkry is vir sonneblom-, canola- en olyfolie wat almal ryk aan poli-onversadigde vetsure is. Die minimale veranderinge in die vetsuurprofiel van MKF dui op die stabiliserende invloed van versadigde vetsure (C16:0 en C18:0) en oleïensuur. Die onstabiliteit van linoleïen- en lineensuur duidelik uit hierdie vetsure se oksidatiewe verval. 'n Afname van 7.41% en 12.80% is waargeneem tussen dae 0 en 240 vir die C18:2/C16:0 en C18:2/C18:0 verhoudings, onderskeidelik. Die voorspelling van die oksidatiewe status van die MKF monsters met behulp van FT-NIR spektroskopie was moontlik deur die ontwikkeling van kalibrasie modelle. 'n Totale datastel van 300 monsters, waarvan ongeveer 'n derde vir validasie aangewend is, is gebruik vir die kalibrasiemodelle. Met behulp van PCA (hoojkomponent analise) kon drie klassifiseerbare groepe by 0, 40 en 80-240 dae onderskei word. Die beste kalibrasiemodel vir PV het 'n standaardfout van voorspelling (SEP) van 0.46 meq.kg", 'n korrellasiekoëffisient (r) van 0.95, 'n oorhelling van 0.02 en 'n standaardfout van voorspelling (RMSEP) van 0.46 meq.kg" gehad. Die CD kalibrasiemodel (geen voorafverwerking) het 'n r van 0.89, SEP van 0.01% oorhelling van 0.001 en RMSEP van 0.01% gehad. Die AV kalibrasie het 'n SEP van 0.32 mmol.kg', oorhelling van 0.03, RMSEP van 0.32 mmol.kg" en r van 0.93 gehad. Die C18:2 en C18:3 modelle is saamgestel deur PLS (partial least squares) regressie. Waardes verkry vir C18:2 en C18:3 was onderskeidelik: SEP 0.32% en 0.05%, RMSEP, 0.32% en 0.05%, oorhelling 0.05 en 0.01 en r 0.82 en 0.54. In die geval van C18:1, C18:0 en C16:0, het die kalibrasies swakker statistiek korrellasies getoon. Goeie korrellasies is verkry tydens kalibrasie vir die C18:2/C16:0 en C18:2/C18:0 verhoudings.

Abstract: Mycelium growth, production and bromatologicals characteristics of shiitake in function of lineages and chemical and physical properties of eucalyptus clones and species were evaluated. In Experiment 1, mycelium growth of two Lentinula edodes (Berk.) Pegler (LE-95/01 and LE-96/18) species in culture mediums prepared with sawdust extract from seven species (E. saligna, E. grandis, E. urophylla, E. camaldulensis, E. citriodora, E. paniculata e E. pellita) and three eucalyptus clones (hybrid E. grandis x E. urophylla) was analyzed. The experimental design was totally randomized, in 2x10 factorial design, totalizing 20 treatments with 10 repetitions, being that each repetition corresponded to one Petri dish. In Experiment 2, mycelium growth of eight L. edodes lineages (LE-96/17, LE-95/02, LE-95/07, LE-98/55, LE-96/18, LE-95/01, LE-96/13 and LE-98/47) in culture mediums prepared with sawdust extract from Eucalyptus spp was evaluated. The experimental design was totally randomized, with 8 treatments and 8 repetitions, being that each repetition corresponded to one Petri dish. In Experiment 3, production and bromatological characterization of two Lentinula edodes lineages cultivated in seven species and three clones of eucalyptus was evaluated. The experimental design was totally randomized, in 2x10 factorial design, totalizing 20 treatments with 40 repetitions, being that each repetition corresponded to one log. In Experiment 4, physical and chemical properties of seven species and three clones of eucalyptus before and after the cultivation of two L. edodes lineages was evaluated. The experimental design was totally randomized, in 2x10 factorial design, totalizing 20 treatments with 9 repetitions, being that each repetition corresponded to one log. The culture medium that provided highest averages of mycelium growth of L. edodes lineages LE-95/01 and LE-96/18 was the one with... (Complete abstract click electronic access below) / Orientador: Marli Teixeira de Almeida Minhoni / Coorientador: José Luiz Stape / Banca: Edson Luiz Furtado / Banca: Claudio Angeli Sansígolo / Banca: Luiz Antônio Graciolli / Banca: Arailde Fontes Urben / Doutor

Orientador: Augusto Ferreira da Eira / Banca: José Raimundo de Souza Passos / Banca: Nelson Barros Colauto / Resumo: As pesquisas sobre o cultivo axênico de shiitake e produção de inóculo, para as condições brasileiras, são escassas. O estudo do crescimento miceliano visa compreender os aspectos físicos, químicos e ambientais que causam alterações no processo desse crescimento. O objetivo deste trabalho foi o de estudar a influência de aspectos nutricionais e a interferência do substrato na cinética de crescimento de linhagens de Lentinula edodes. Os materiais utilizados foram duas linhagens de Lentinula edodes: L17 e L55 da micoteca do Módulo de Cogumelos da FCA e substratos à base de serragem (S) e bagaço de cana-de-açúcar (B) com a adição de três quantidades de farelos de arroz e de trigo (metade de cada): 0, 10 e 20%, perfazendo 6 tratamentos, os quais foram utilizados na cinética da área de crescimento miceliano em meio de cultura e do volume de crescimento em substrato. Dos resultados obtidos foram extraídas as seguintes conclusões: A cinética de crescimento miceliano em superfície (área), independente das linhagens e substratos, seguiu um modelo matemático representado por uma equação exponencial. Os parâmetros estimados gama tiveram uma relação com a velocidade final instantânea de crescimento em área. A cinética de crescimento miceliano em volume, independente das linhagens e substratos, seguiu um modelo matemático representado por equação logarítmica. Os parâmetros estimados betas, gama e delta, não apresentaram relação com a velocidade de crescimento em volume. Ocorreram interações significativas entre linhagens, substratos base e quantidades de farelos, tanto na cinética de crescimento em superfície quanto em volume. A linhagem L55 se apresentou mais adaptada à metodologia adotada por ser utilizada em cultivo axênico. / Abstract: In Brazil there was little research related to Shiitake axenic culture. It was researched in this experiment the physical, chemical and environmental aspects in relation to different strains of Lentinula edodes. The aim of this research was to understand the substratum effects in the kinetics of the Shiitake mycelium growth. It was used two Shiitake strains and two different base substrate (eucalyptus sawdust and sugar cane bagasse) varying in three proportions of the supplements. The supplements, a blend of rice and wheat brans, were added in the proportion of 0, 10 and 20% of the base substrate. The experiment was composed of six treatments. It was concluded that the mycelium kinetics growth in culture medium followed a mathematical model that were represented by exponential equation. Gamma parameters were directly proportional to the instantaneous growth velocity in area. The mycelium growth kinetics in volume had no effect relation to the strains and substrate and it followed a mathematical model represented by logarithmic equation. Beta, gamma and delta parameters didn't show any correlation with the growth velocity in volume. There were significant differences between the strains and the mycelium growth in the supplemented substrate. The strain L55 was better adapted than L17. / Mestre

Master of Science / Department of Horticulture and Natural Resources / Candice A. Shoemaker / In our ever-growing urban environments food security is dwindling. Healthy food may be difficult to find in city centers, but publicly owned land is still common. In many cities, a significant percentage of green space is publicly accessible and regularly maintained. Under appropriate circumstances these green spaces can be utilized to grow edible food and benefit the cities and communities they are placed in. Claims of the benefits of public edible landscapes include: beautification, strengthening communities, food security, ecological services, self-sufficiency, education and may lead to a more positive attitude towards urban agriculture. Existing organizations working with public edible landscapes in three US municipalities of varying size were used as case studies to explore strategies and challenges in proposing, implementing and maintaining public edible spaces. Interviews were conducted with representatives from the Beacon Food Forest in Seattle, WA, the Dr. George Washington Carver Edible Park in Asheville, NC, and the Upper Valley Apple Corps in Hartford, VT. These case studies identified common concepts related to the success of public edible landscapes: a presence of community interest, actively involved individuals with a skill set in food production, the presence of an umbrella or advocacy organization, and support from city officials. A discussion of approaches being used by others could provide the foundation for future research into the effects of introducing edible plants into public green space on the local community and environment.