Browsing by Author "Irungu, F. G."

Now showing 1 - 3 of 3

Nutritional and microbial quality of extruded fish feeds containing black soldier fly (Hermetia illucens L) larvae meal as a replacement for fish meal for Nile Tilapia (Oreochromis niloticus) and African sharptooth catfish (Clarius gariepinus)
(Taylor & Francis, 2021-05-24) Were, G. J.; Irungu, F. G.; Ngoda, P. N.; Affognon, H.; Ekesi, S.; Nakimbugwe, D.; Fiaboe, K. K. M.; Mutungi, C. M.; ; ;
The black soldier fly (Hermetia illucens L.) is a potential substitute of fish meal in feeds. However, information on the nutrition and safety of these feeds is inadequate. This study examined the quality of fish feed pellets extruded from blends formulated with and without black soldier fly larval meal (BSFLM). A further aim was to study the influence of extrusion processing types on feed composition. Two iso-proteinous feed blends containing 28% protein were formulated with 0% BSFLM (BSFLM0) and 75% BSFLM (BSFLM75). The feed blends were then cold- or hot-extruded (CE or HE) and the products analyzed for proximate composition, amino acids, fatty acid profiles and microbial content. The BSFLM75_HE pellets contained significantly higher levels of fat (15.6%), leucine (11.5 mg/g), and oleic acid (79.1 µg/g). Hot extrusion concentrated phenylalanine and leucine, increased polyunsaturated fatty acids and saturated fatty acids and decreased total viable counts, coliforms, yeast and molds, endospores and Salmonella.
Static and Varied Magnetic Fields Effects on Shrinkage and Sprouting Characteristics of Stored Potatoes
(Taylor & Francis Group, 2022) Irungu, F. G.; Mahungu, S. M.; Mathenge, S. G.; Mutungi, C. M.; Ndiritu, F. G.
The effects of static and varying magnetic fields (MF) on shrinkage and sprouting characteristics of stored potatoes were studied. Static MF was produced by the use of direct current (DC), while alternating current (AC) produced varying MF. Intensities of DC MF were set at 0.5, 1.0, 1.5, and 2.0 mT and those of AC MF set at 0.2, 0.4, 0.6 and 0.8 mT. The exposure time of DC MF on potatoes was held at 10, 20, 40, 60, and 120 s, while the exposure time of AC MF was 10, 20, 40, 80, and 160s. Potatoes were then stored in a dark room, with light intensity and temperature of 0 lm/m2 and 14 ± 2 °C, respectively, for 8 weeks after which they were examined. Weight reduction was significantly (P < 0.05) lower in potatoes that were subjected to both DC and AC MF than in the untreated tubers. However, it is the DC MF of 2.0 mT that resulted in low acceptable weight loss of less than 10%. Fewer numbers of sprouts per tuber were observed in potatoes that were exposed to DC MF of 0.5, 1.0, and 2.0 mT for 60 s or AC MF of 0.4, 0.6, and 0.8 mT for 80 s, respectively. Our results provide important insights on the applicability of static and varying magnetic fields on reduction of postharvest losses in potatoes.
Use of Magnetic Fields Reduces α-chaconine, α-solanine, and Total Glycoalkaloids in Stored Potatoes (Solanum tuberosum L.)
(Wiley Periodicals LLC., 2022) Irungu, F. G.; Tanga, C. M.; Ndiritu, F. G.; Mwaura, L.; Moyo, M.; Mahungu, S. M.
This work aimed to assess the suitability of magnetic fields (MF) to reduce glycoal- kaloids (GAs) in stored potatoes. The effects of the source of magnetic fields (direct current [DC] and alternating current [AC]), magnetic field intensity (1, 2, and 3 mT), and storage type (dark store—herein referred to as the control store and a commercial store with varying light intensity) on quantities of GAs were investigated. Subjecting tubers to increasing levels of MF intensities and placing them in the control store led to a significant (p < .05) decrease in α-chaconine and an increase in α-solanine. However, storage of potatoes in the commercial store after exposure to increasing MF intensities led to a significant (p < .05) decrease in α-solanine and an increase in α- chaconine. The use of AC MF with an intensity of 2 mT resulted in a significant (p < .05) reduction in α-chaconine, α-solanine, and TG. Novelty impact statement: Magnetic fields are an emerging non-thermal technology that has wide potential in food processing applications. The findings in the current work revealed that magnetic fields can be used to reduce quantities of toxic glycoal- kaloids in potatoes during storage, and thus improve their postharvest quality. The results offer practical insights on postharvest management of potatoes to ensure re- duction of losses and thus positively impact food and nutritional security.