Ada Rocha

Shelf life of minimally processed apple (cv. Jonagored) determined by colour changes

Abstract Physical, chemical and sensory changes of cut apple (cv. Jonagored) stored in the dark at 4 °C were evaluated. Colour was found to be the critical parameter for this product. Apple cubes underwent severe surface browning primarily during the initial days of storage. The shelf-life of cut apple was therefore very limited, to three days maximum. Sensory analyses and objective quality evaluations of cut apple were considered highly correlated in terms of colour and flavour, especially with respect to fructose and sucrose, showing that the selected sensory attributes were good indicators of overall fruit quality.

Characterization of polyphenoloxidase (PPO) extracted from "Jonagored" apple

Abstract Polyphenoloxidase (PPO) was extracted from apple (cv. Jonagored) with addition of 2% PVP and 0.25% Triton X100 to the extraction buffer containing phenolic adsorbents. Experiments were performed to evaluate the affinity and specificity towards several substrates. ‘Jonagored’ apple PPO was found to have higher specificity (lower Km) towards L-dopa, 4-methylcatechol and (+) catechin than other phenols tested, but the highest activity level was obtained with p-cresol. The ratio Vmax/Km indicates that p-cresol followed by L-dopa and 4-methylcatechol are the best substrates for ‘Jonagored’ apple PPO. The enzyme activity showed two pH optima, at 5.0 and 7.5, at room temperature, with the main peak at pH 7.5 and the secondary one at pH 5.0 when catechol was the substrate.

Shelf-life of chilled cut orange determined by sensory quality

Abstract The shelf-life of chilled cut orange was evaluated in terms of physical and chemical quality characteristics, microbial contamination and sensorial acceptability. After minimal processing (peeling and cutting), fresh orange was stored in air at 4 °C. Evaluations were performed at different times of storage. The respiration rate of the fresh-cut orange was also evaluated. No significant increase was noticed in relation to the whole fruit which means that this was not the factor responsible for an accelerated deterioration of the product. During the first eight days of storage the major quality parameters remain almost unchangeable, except for titratable acidity which decreased around 36% and ascorbic acid content which decreased around 22%. With respect to microbial contamination low temperature determined a considerable shelf-life (15 days). Sensory quality was the parameter which determined the shelf-life of cut orange to five days at 4 °C due to flavour changes.

Characterisation of Starking apple polyphenoloxidase

Experiments were performed to optimise the extraction conditions of ‘Starking’ apple fruit polyphenoloxidase (PPO), to evaluate the affinity and specificity towards several substrates and to study the stability of enzyme extracts from apple samples stored under different conditions. Sodium phosphate buffer (0·2 M, pH 6·5) plus 0·25% Triton X100 and 1% or 2% PVPP was found to be the most efficient extraction medium. Chlorogenic acid, dopamine and 4-methylcatechol showed similar specificity towards PPO, and chlorogenic acid was found to be the best substrate for the enzyme. Enzyme extracts from frozen cut apple stored at −4°C, and extracts from lyophilised apple samples stored at 4°C were more stable than extracts obtained from fresh-cut or acetone powder samples.

Modified atmosphere package for apple ‘Bravo de Esmolfe’

Abstract Apple ‘Bravo de Esmolfe’ original from the parish of ‘Esmolfe’ is cultivated in specific regions of Portugal. This cultivar of medium to low production requires very low temperatures, but it is extremely sensitive to frost. The aim of this work was to evaluate the influence of modified atmosphere on the quality of apple (cv. Bravo de Esmolfe) during cold storage. Apples packed in modified atmosphere lost less weight, presented better colour, and preserved better firmness than fruits stored in air.

Determination of plate waste in primary school lunches by weighing and visual estimation methods: A validation study

The aim of this study was to validate the visual estimation method for aggregated plate waste of main dish at Portuguese primary school canteens. For this purpose plate waste at school lunch was measured for 505 individual servings, using weighing individual servings and plate waste and visual estimation method by a 6-point scale, as developed by Comstock et al. (1981). A high variability of initial serving weights was found with serving sizes ranging from 88.9 to 283.3g and with a coefficient of variation ranging from 5.5% to 24.7%. Mean plate waste was 27.5% according to the weighing method. There was a significant bias in the conversion of the visual waste estimations to actual waste, being overestimated by an average of 8.0 g (ranging from -12.9 g to 41.4 g). According to Bland and Altman plot, the mean difference between methods was of 8.0 g and the amplitude interval was 102.6g. The study showed that the visual estimation method is not as accurate as the weighing method in assessing nonselective aggregated plate waste at primary school canteens. Our findings are thus very important on considering plate waste assessment, since the wide variation on initial servings introduces a relevant bias when considering standard portions or a random sample of initial servings. Although, greater convenience, time-saving and the possibility to monitor plate waste of large groups, make the visual estimation method an important method to assess plate waste at school canteens, these results highlighted the need of portions standardization and control of initial servings to allow for its use.

Food waste as an index of foodservice quality

Purpose – The purpose of this paper is to evaluate waste at a Portuguese university setting in order to suggest improvements on foodservice sustainability. Design/methodology/approach – The work was developed during four weeks in order to allow the evaluation of parameters of an entire menu cycle. The index of waste/consumption (%) was obtained by the ratio between plate waste and the quantity of foods distributed, subtracting the weight of leftovers. Findings – The average index of waste/consumption was approximately 24 percent, higher in the days with a fish menu, values considered unacceptable. Each canteen user is served with approximately 940 g of foods, from which only 660 g were effectively consumed, corresponding to 80 g of leftovers and 200 g of waste. Originality/value – It seems possible and desirable to reduce food waste in order to optimize food unit profitability and sustainability. Reducing food waste will contribute to improve foodservice quality as well as consumers satisfaction. Potenti...

Salt reduction in vegetable soup does not affect saltiness intensity and liking in the elderly and children

Study background Reduction of added salt levels in soups is recommended. We evaluated the impact of a 30% reduction of usual added salt in vegetable soups on elderly and childrens saltiness and liking evaluation. Methods Subjects were elderly and recruited from two public nursing homes (29 older adults, 79.7±8.9 years), and preschool children recruited from a public preschool (49 children, 4.5±1.3 years). This study took place in institutional lunchrooms. Through randomization and crossover, the subjects participated in two sensory evaluation sessions, on consecutive days, to assess perceived saltiness intensity (elderly sample) and liking (elderly and children samples) of a vegetable soup with baseline salt content and with a 30% salt reduction. Elderly rated perceived liking through a 10 cm visual analogue scale [‘like extremely’ (1) to ‘dislike extremely’ (10)] and children through a five-point facial scale [‘dislike very much’ (1) to ‘like very much’ (5)]. Results After 30% added salt reduction in vegetable soup, there were no significant differences in saltiness noted by the elderly (p=0.150), and in perceived liking by children (p=0.160) and elderly (p=0.860). Conclusions A 30% salt reduction in vegetable soup may be achieved without compromising perceived saltiness and liking in children and the elderly.

Female Sexual Function and Depression After Kidney Transplantation: Comparison Between Deceased- and Living-Donor Recipients

Disturbances in sexual function and depression are a common feature in women with chronic renal failure. Living-donor kidney transplantation seems to warrant better results than its cadaveric counterpart in many aspects but its impact on post-transplantation sexual function remains unknown. This study aimed to compare post-transplantation sexual function and depression in women receiving kidney grafts from living and deceased donors. From a single-center prospective database of 2016 renal transplantations between June 2011 and June 2013, we enrolled 50 sexually active women after kidney transplantation. Female sexual function was evaluated with the Female Sexual Function Index Questionnaire (FSFI) and depression was assessed using the Beck Depression Inventory-II (BDI-II) scale. Thirty-four patients referred the questionnaires. The sexual domains of satisfaction and desire were significantly better in living-donor receptors; in all other domains evaluated by FSFI no statistically significant difference was encountered between groups, although living-donor receptors tended to report better function. Total BDI-II was well correlated with total FSFI score in our study cohort (Spearmans rho = -0.80, P < .001). Only 34.6% of women referred to have discussed sexual issues with their physicians before transplantation, whereas 73.1% stated it would have been important. In conclusion, living-donor transplantation exerted a positive effect on womens sexual function.

System of planning and evaluation of school meals

OBJECTIVE To develop a software to plan and evaluate school meals according to the main national and international standards for foods and nutrition. DESIGN Development of software. SETTING Public schools, Portugal. SUBJECTS School meals for students. RESULTS The System of Planning and Evaluation of School Meals (SPARE) is a software that allows the planning of school meals in an effective and organized way, according to the main national and international standards for food and nutrition. The regular use of this tool enables the evaluation, monitoring and verification towards continuous improvement of the quality of school meals. CONCLUSIONS The SPARE software aims to promote healthy eating by focusing on the planning and production of safe and adequate meals in the school environment. This software can be adapted to different age groups and to different contexts, attending to specific nutritional and food standards.