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Investigation on the potential of applying bio-based edible coatings for horticultural products exemplified with cucumbers
Plastic packaging for fresh horticultural produce has many advantages but generates plastic waste and ecological alternatives are required. Edible coatings can retard many processes related to loss of quality. Hydrophobic lipid-based coatings are preferably applied for fresh fruits and vegetables. The approval of such coatings for products with edible peels in EU is increasingly under discussion. However, investigations on the efficiency of various edible coatings on soft-skinned fruit and vegetables are rare and it is currently unclear whether the consumer will accept them. Therefore, this study investigates (1) important characteristics of a lipid-based coating and (2) its ability to maintain the post-harvest quality of fresh cucumbers. This was evaluated by a comparative storage test under common suboptimal retail conditions (20 °C; 65% RH). The study also evaluates (3) the general perception of consumers about and their acceptance of the application of edible coatings on fresh fruit and vegetables with edible peels. The investigated coating was able to drastically reduce water loss (54–68%) and fruit respiration (approx. 33%) of fresh cucumber. The reduction of tissue stiffness was delayed by 2 days, thus, prolonged shelf life. Majority of consumer (77%) endorse the application of edible coatings as an alternative to plastic packaging, but emphasized important requirements for them.
Colour change kinetics of pumpkin (Cucurbita moschata) slices during convective air drying and bioactive compounds of the dried products
The high contents of bioactive compounds make the pumpkin fruit an important crop for the development of novel functional foods for improving food security, nutrition and health. This study investigated the effect of drying air temperatures (50, 60 and 70 °C) and slice thicknesses (3 and 5 mm) on the drying behaviour, colour change kinetics and bioactive compounds content of the dried pumpkin slices. The effective moisture diffusivity of pumpkin increased from 2.860 × 10−10 to 9.815 × 10−10 m2/s as drying temperature increased while activation energy values ranged between 47.14 and 51.60 kJ/mol. After the drying process, Lightness (L*) and yellowness (b*) values of pumpkin decreased from 74.61 ± 1.18 to 56.50–70.15 and 61.95 ± 2.03 to 51.90–56.10, respectively whereas redness (a*) and total colour difference (ΔE) increased from 8.47 ± 0.09 to 9.98–11.07 and 0 to 10.01–17.12, respectively. Changes in L* and b* values during drying were adequately predicted by the first-order reaction kinetics while a* and ΔE followed zero-order reaction kinetics (R2 = 0.9765 to 0.9978). The reaction rate constants for colour change greatly depended on the drying air temperature. Contents of β-carotene, ascorbic acid, total phenols, flavonoids and antioxidant activity of the dried pumpkins varied between 43.80 and 58.15 μg g−1, 37.62–50.13 mg/100g, 109.60–155.92 mg GAE/100g, 49.68–67.74 mg kaempferol/100g and 61.45–80.72%, respectively. Predominantly, an increase in pumpkin slice thickness prolonged drying time and caused a greater loss of bioactive compounds and antioxidant activity. Moreover, β-carotene and ascorbic acid contents were higher in 60 °C dried pumpkin than those dried at 50 °C and 70 °C. Nonetheless, increasing the drying air temperature increased the total phenolic compounds and flavonoid contents in dried pumpkin products. The study results could be useful for the food industry and further research work.
This looks More Like that: Enhancing Self-Explaining Models by prototypical relevance propagation: This Looks More Like That
Current machine learning models have shown high efficiency in solving a wide variety of real-world problems. However, their black box character poses a major challenge for the comprehensibility and traceability of the underlying decision-making strategies. As a remedy, numerous post-hoc and self-explanation methods have been developed to interpret the models’ behavior. Those methods, in addition, enable the identification of artifacts that, inherent in the training data, can be erroneously learned by the model as class-relevant features. In this work, we provide a detailed case study of a representative for the state-of-the-art self-explaining network, ProtoPNet, in the presence of a spectrum of artifacts. Accordingly, we identify the main drawbacks of ProtoPNet, especially its coarse and spatially imprecise explanations. We address these limitations by introducing Prototypical Relevance Propagation (PRP), a novel method for generating more precise model-aware explanations. Furthermore, in order to obtain a clean, artifact-free dataset, we propose to use multi-view clustering strategies for segregating the artifact images using the PRP explanations, thereby suppressing the potential artifact learning in the models.
Upgrading pasta wastes through lactic acid fermentations
During its production process, every kilogram of pasta manufactured generates about 23 g of pasta wastes (PW). Considering the global pasta production, there are about 376 kilotonnes of PW produced every year. In this work, PW were characterised and used as the substrate in lactic acid (LA) fermentations. Enzymatic hydrolysis of 200 g/L of PW allowed for the liberation of sugars with a yield 0.81 gs/gdryPW. After the screening of several B. coagulans, the strain A559 was selected for experiments at the lab and pilot scales. Two fermentation modes were tested during lab scale experiments namely, simultaneous saccharification and fermentation and sequential hydrolysis and fermentation with the latter showing higher yields. The process was scaled up to 50 L where a LA concentration of 47.67 g/L and yield of 0.67 gLA/gdrydPW were achieved.
Perspectives from CO+RE: How COVID-19 changed our food systems and food security paradigms
[no abstract available]
Stability of hepatitis E virus at high hydrostatic pressure processing
Hepatitis E virus (HEV) is the causative agent of acute and chronic hepatitis in humans. The zoonotic HEV genotype 3 is the main genotype in Europe. The foodborne transmission via consumption of meat and meat products prepared from infected pigs or wild boars is considered the major transmission route of this genotype. High hydrostatic pressure processing (HPP) is a technique, which can be used for inactivation of pathogens in food. Here, preparations of a cell culture-adapted HEV genotype 3 strain in phosphate-buffered saline (PBS) were subjected to HPP and the remaining infectivity was titrated in cell culture by counting fluorescent foci of replicating virus. A gradual decrease in infectivity was found by application of 100 to 600 MPa for 2 min. At 20 °C, infectivity reduction of 0.5 log10 at 200 MPa and 1 log10 at 400 MPa were observed. Slightly higher infectivity reduction of 1 log10 at 200 MPa and 2 log10 at 400 MPa were found by application of the pressure at 4 °C. At both temperatures, the virus was nearly completely inactivated (>3.5 log10 infectivity decrease) at 600 MPa; however, low amounts of remaining infectious virus were observed in one of three replicates in both cases. Transmission electron microscopy showed disassembled and distorted particles in the preparations treated with 600 MPa. Time-course experiments at 400 MPa showed a continuous decline of infectivity from 30 s to 10 min, leading to a 2 log10 infectivity decrease at 20 °C and to a 2.5 log10 infectivity decrease at 4 °C for a 10 min pressure application each. Predictive models for inactivation of HEV by HPP were generated on the basis of the generated data. The results show that HPP treatment can reduce HEV infectivity, which is mainly dependent on pressure height and duration of the HPP treatment. Compared to other viruses, HEV appears to be relatively stable against HPP and high pressure/long time combinations have to be applied for significant reduction of infectivity.