Roselle anthocyanin stability profile and its potential role in post-harvest deterioration: A review

The conversion of roselle calyx into a dried extract without decreasing its consistency is a challenge, given the perishability of the calyx and instability of anthocyanin, which can quickly degrade and develop colored or unwanted brown colors because of its high reactivity. The most critical factors influencing anthocyanins' stability are pH, temperature, light and post-harvest-related enzymes. Besides, the calyx suffered wound injury when removing seed from the calyx, causing stress and eventually, microbial degradation. Nonetheless, mature anthocyanins stimulate plants by responding to stress, especially drought, high salinity, excess light and injury; it is also correlated with improved stress resistance as the genes of individual plants are triggered under these conditions modulate anthocyanin biosynthesis. This work investigates the stability and potential role of roselle anthocyanin in post harvest deterioration. Anthocyanin stability can, therefore, be achieved by maintaining low pH and temperature, acylation, glycosylation, copigmentation and encapsulation. In the quest for roselle deterioration biomarkers, the detection of critical enzymes, such as Chalcone synthase CHS and FH3 Flavanone 3 hydroxylase, would offer insight into the genetic modification of anthocyanin.

Molecular Characterization of Post Harvest Fungus Associated with Spoilt Broccoli

Broccoli (Brassica oleracea var. italica) is a nutritional vegetable that looks like a small tree. Despite the fact that it is extensively loaded with arrays of vitamins, minerals, fiber and antioxidants, it has been observed that it has a short lifespan of not more than 2-5 days due to post-harvest deterioration. A study was conducted to isolate and identify the common fungal pathogens causing post-harvest deterioration of broccoli crown. Diseased broccoli crowns were collected from Ogunabali Fruit Garden Market in D-Line, Port Harcourt Local Government Area of Rivers State. Fungal isolates were collected and morphologically identified. The DNA of the most common fungal isolate, BC-3B was molecularly characterized using Internal Transcribed Spacer 4 and 5 (ITS-4 and 5) molecular markers. The morphological studies revealed that the BC-3B isolate was an Aspergillus niger. The BC-3B isolate DNA sequence was aligned using Basic Local Alignment Search Tool for Nucleotide (BLASTN) 2.8.0 version of National Center for Biotechnology Information (NCBI) database. The molecular weight of the DNA of the isolates was over 600base pairs. Based on sequence similarity, it was observed that the broccoli isolate BC-3B was 93% identical to Aspergillus niger. From the above results, these findings showed that Aspergillus niger is the causal fungal pathogen of post-harvest rot of broccoli. Phylogenetic tree was constructed to access the relationship between the isolates obtained from this study. This study has provided information on some of the fungal organisms found in broccoli. It is anticipated that this result will provide information for disease control approach for alleviating the post-harvest losses of broccoli caused by Aspergillus niger and provide a foundation for further study of possible harm of consuming diseased broccoli.

Autonomous solar thermal system design for indirect dehydration of Aguaymanto (Physalis Peruviana L.), Junín

This paper aimed to design an autonomous indirect solar dryer, which can dehydrate the aguaymanto in a costeffective manner, yielding a quality product suitable for export from the central part highland of Peru. To complete this task, it was proposed to design a prototype of autonomous solar dryer of 100 kg per batch of aguaymanto, equipped with flat reflectors and forced air feed, and powered with photovoltaic energy. This system allows to dry aguaymanto fruit at the requirements needed for its exportation. The fryer has the following dimensions: inner dimensions of the drying chamber: bottom 0.60 m, width 1.40 m, and height 1.10 m, with additional 0.05 m for insulation. Hence, the outer measures are bottom 0.70 m, width 1.50 m, and height 1.20 m. Two solar collectors are proposed with the dimensions of each: 1.50 m wide, 2.40 m long, and 0.15 m height; 2 flat mirror reflectors are required. A 80 Wp photovoltaic panel was selected for the forced air system and process control. This solar dryer is expected to cope with the problem of post-harvest deterioration. Also, it will facilitate the export by improving product quality and providing a cost-effective technology.

A Study of Fungal Diseases Occurring on Stored Tomatoes of Balkhu Agriculture and Vegetable Market, Nepal

Tomatoes are one of the most widely produced and consumed vegetable in Nepal. Fungal pathogens deteriorate the quality and quantity of tomato and cause health hazards to the consumers as well as economic loss to the traders. This study was carried out to identify some fungal diseases associated with post-harvest deterioration of stored tomato fruits in Balkhu Agriculture and vegetable Market of Kathmandu, Nepal. Collected samples were cultured in Potato Dextrose Agar (PDA) media in complete randomized design. Fifteen species of fungi namely Alternaria alternata, A. solani, Aspergillus niger, Botrytis cinerea, Fulvum fulva, Colletotrichum truncatum, Curvularia spicifera, Fusarium oxysporum, Dipodascus geotrichum, Mucor mucedo, Penicillium chrysogenum, Phytophthora infestans, Boeremia exigua, Pythium aphanidermatum and Rhizopus stolonifer were identified. These were responsible for 14 different diseases of Alternaria fruit rot, Anthracnose, Black mold rot, Botrytis Bunch Rot, Damping off/ fruit rot, Drechslera mold, Fusarium rot, Mucor rot, Penicillum rot, Boeremia blight, Phytophthora rot, Rhizopus rot, Russet, and, Sour rot. The presence of these fungi and corresponding rot diseases on stored tomato indicates the need for management of fungi, farm sanitation and improved market in order to prevent field-to-storage transmission of pathogen.