A lettuce moisture detection method based on terahertz time-domain spectroscopy / Um método de detecção de umidade de alface baseado em THz-TDS

For non-destructive detection of water stress in lettuce, terahertz time-domain spectroscopy (THz-TDS) was used to quantitatively analyze water content in lettuce. Four gradient lettuce water contents were used . Spectral data of lettuce were collected by a THz-TDS system, and denoised using the S-G derivative, Savitzky-Golay (S-G) smoothing and normalization filtering. The fitting effect of the pretreatment method was better than that of regression fitting, and the S-G derivative fitting effect was obtained. Then a calibration set and a verification set were divided by the Kennan-Stone algorithm, sample set partitioning based on joint X-Y distance (SPXY) algorithm, and the random sampling (RS) algorithm, and the parameters of RS were optimized by regression fitting. The stability competitive adaptive reweighted sampling, iteratively retained information variables and interval combination optimization were used to select characteristic wavelengths, and then continuous projection was used on basis of the three algorithms above. After the successive projection algorithm was re-screened, partial least squares regression was used into modeling. The regression coefficients R²c and RMSEC reach 0.8962 and 412.5% respectively, and R²p and RMSEP of the verification set are 0.8757 and 528.9% respectively.

Para a detecção não destrutiva de estresse hídrico da alface, espectroscopia no domínio do tempo em terahertz (THz-TDS) foi usada para analisar quantitativamente o conteúdo de água na alface. Quatro gradientes de conteúdo de água de alface foram usados. Os dados espectrais da alface foram coletados por um sistema THz-TDS e denoised usando o derivado S-G, Savitzky-Golay (S-G) suavização e filtragem de normalização. O efeito de ajuste do método de pré-tratamento foi melhor do que o do ajuste de regressão, e o efeito de ajuste da derivada S-G foi obtido. Em seguida, um conjunto de calibração e um conjunto de verificação foram divididos pelo algoritmo Kennan-Stone, particionamento do conjunto de amostra com base no algoritmo de distância X-Y conjunta (SPXY) e o algoritmo de amostragem aleatória (RS), e os parâmetros de RS foram otimizados por ajuste de regressão. A amostragem adaptativa de estabilidade competitiva reponderada, variáveis de informação retidas iterativamente e otimização de combinação de intervalo foram usadas para selecionar comprimentos de onda característicos e, em seguida, a projeção contínua foi usada com base nos três algoritmos acima. Depois que o algoritmo de projeção sucessivo foi reprojetado, a regressão de mínimos quadrados parcial foi usada na modelagem. Os coeficientes de regressão R2 e erro quadrático médio (RMSEP) atingem 0,8962 e 412,50%, respectivamente, e R2 e RMSEP do conjunto de verificação são 0,8757 e 528,93%, respectivamente.

Relationship between Physicochemical Characteristics and Pathogenic Leptospira in Urban Slum Waters.

Leptospirosis, a zoonosis caused by pathogenic Leptospira, primarily affects tropical, developing regions, especially communities without adequate sanitation. Outbreaks of leptospirosis have been linked with the presence of pathogenic Leptospira in water. In this study, we measured the physicochemical characteristics (temperature, pH, salinity, turbidity, electrical conductivity, and total dissolved solids (TDS)) of surface waters from an urban slum in Salvador, Brazil, and analyzed their associations with the presence and concentration of pathogenic Leptospira reported previously. We built logistic and linear regression models to determine the strength of association between physicochemical parameters and the presence and concentration of Leptospira. We found that salinity, TDS, pH, and type of water were strongly associated with the presence of Leptospira. In contrast, only pH was associated with the concentration of the pathogen in water. The study of physico-chemical markers can contribute to a better understanding of the occurrence of Leptospira in water and to the identification of sources of risk in urban slum environments.

Cross-modal interactions as a strategy for sugar reduction in products targeted at children: Case study with vanilla milk desserts.

The high availability of products with high sugar content, particularly among those targeted as children, has been identified as one of the factors that contribute to the childhood obesity epidemic. For this reason, product reformulation has been recommended as one of the strategies that can be implemented to achieve short-term reductions in children's sugar intake. In this context, the objective of this study was to evaluate the feasibility of using cross-modal (taste-odor-texture) interactions as a strategy for reducing the sugar content of products targeted at children, using milk desserts as case study. A series of 5 vanilla milk desserts were formulated: a control sample with 12% added sugar and 4 sugar-reduced samples (7% added sugar) prepared following a 2 × 2 experimental design by varying vanilla (0.4% and 0.6% w/w) and starch (4.3% and 4.7% w/w) concentrations. A total of 112 children (8-12 years old) tasted the desserts and performed a dynamic sensory characterization task using either temporal check-all-that-apply or temporal dominance of sensations. In addition, they assessed the overall liking of all samples. Results showed that sugar-reduced samples did not significantly differ from the control sample in terms of their average overall liking scores. However, individual differences in children's hedonic reaction were found; three clusters of children with distinctive liking patterns were identified. The increase in vanilla and starch concentration led to an increase in overall liking for over 80% of the children. Sensory dynamic profiles revealed significant but subtle differences among samples. Results from the present work suggest that cross-modal interactions could contribute to minimizing the sensory changes caused by sugar reduction, which could enable to achieve larger reductions if implemented in the context of gradual sugar reduction programs.

Temporal dominance of sensations and preferences of Brazilians and Slovakians: A cross-cultural study of cachaças stored with woods from the Amazon rainforest.

BACKGROUND: Brazilians and Slovakians evaluated the temporal profile and the acceptability of cachaça stored with different woods (Cumarurana (CM), Jatobá (JT) and, Louro-vermelho (LV), which are found in the Amazon rainforest, and also oak), with the aim of performing a cross-cultural comparison of the dynamic profile of the attributes perceived in the cachaças and the sensorial acceptance of the samples. RESULTS: Important differences were observed between the temporal sensorial profiles generated by the two groups and their preferences. Brazilians preferred cachaças stored with the traditional wood, oak, followed by those stored with JT and CM. In contrast, Slovakians preferred cachaças stored with JT, followed by those stored with LV and oak. For both countries, the dominance of wood flavor and vanilla attributes at the end of the analysis time was positively associated with acceptance, while the dominance of off-flavors and the wood flavor attribute at the beginning of the analysis time was negatively associated with acceptance for Brazilians and Slovakians, respectively. CONCLUSION: Brazilians preferred cachaça stored with oak wood, and Slovakians preferred cachaça stored with JT wood, with acceptability being strongly associated with the dominance of wood flavor and vanilla attributes at the end of the evaluation time. © 2018 Society of Chemical Industry.

Sodium reduction in margarine using NaCl substitutes

ABSTRACT Sodium chloride is traditionally used as a food additive in food processing. However, because of its high sodium content, NaCl has been associated with chronic diseases. Margarine is a popular product that is used in several preparations, but it includes high sodium content; therefore, it is among the products whose sodium content should be reduced. Thus, the objective of this study was to produce margarines with reduced sodium content prepared using a salt mixture. The following 4 margarine formulations were prepared: Formulation A (control - 0% sodium reduction), Formulation B (20.8% less sodium), Formulation C (33.0% less sodium) and Formulation D (47.4% less sodium). The low sodium formulations were produced using a salt mixture consisting of NaCl, KCl, and monosodium glutamate at different concentrations. The margarines were evaluated using an acceptance test and descriptive tests: time-intensity and temporal dominance of sensations. The mixture used is a good alternative for preparing low sodium margarine because the low sodium formulations feature equal salinity and do not produce a strange or bad taste. Furthermore, it may be possible to prepare margarines with up to 47.4% less sodium and that are acceptable to consumers.

Miracle fruit: An alternative sugar substitute in sour beverages.

High sugar consumption has been related to several chronic diseases and thus, many alternative sweeteners have been extensively researched. However, there is still controversy regarding the harmful effects of their consumption, mainly regarding the use of artificial sweeteners, controversy which increases the demand for natural sweeteners, such as miracle fruit. This tropical plant grows in West Africa is named for its unique ability of changing a sour taste into sweet. Therefore, this study aimed to characterize the temporal profile of miracle fruit and assess its sugar substitute power in sour beverages through time-intensity and temporal dominance of sensations tests. For this, unsweetened lemonade and lemonades with sugar, sucralose and previous miracle fruit ingestions were evaluated. We noted that the dynamic profile of lemonade ingested after miracle fruit ingestion indicates that it seems to be a good sugar substitute, since it provides high sweetness intensity and persistence, reduced product sourness and an absence of aftertastes. The miracle fruit also provided a sensory profile similar to that of sucralose, an established and recognized sugar substitute. The results of this study provide important information for future applications of miracle fruit as a sugar substitute in sour beverages, providing an alternative use for a natural substance as a sweetening agent.