Effect of Different Drying Techniques on the Quality of Garlic: A Comparative Study

Influence of the packaging material and storage temperature on the shelf life of garlic powder

The effect of the packaging materials and storage temperatures on the quality characteristics of the (convective dried at 55 °C and mechanical grounded) garlic powder, was studied for a period of 120 days. The quality parameters such as moisture content, flavour strength, pH, total soluble solids, titrable acidity, change in colour etc. as affected by the packaging materials (LDPE and HDPE) and storage temperatures (Room temperature, refrigerated storage at 4 °C, storage at - 10 °C). The results showed that there was a significant effect of the storage temperature and packaging materials on the quality parameters of the garlic powder. The quality characteristics of garlic powder namely, moisture content (from 6.54 to 7.31 per cent), pH (from 5.57 to 5.69), total soluble solids (from 36.6 to 38.9°BX) and change in colour (from 7.07 to 17.12 per cent) were increased whereas flavour strength (from 0.219 to 0.192 per cent) and titrable acidity (from 0.67 to 0.62) of garlic powder were decreased with the increase of the storage period. Garlic powder packed in low density polyethylene and stored at - 10 °C retained the quality after storage.

Physical and chemical characteristics of Asian sea bass bio-calcium powders as affected by ultrasonication treatment and drying method

The effects of ultrasonication and drying method on particle size and other product characteristics of bio-calcium powder from Asian sea bass (Lates calcarifer) backbone were investigated. Ultrasonication was performed at different amplitudes (60%, 70%, and 80%) for varying periods (15 and 30 min). Ultrasonication at higher amplitudes for a longer time reduced the powder particle size more effectively (p < .05), but had no impact on zeta potential (p > .05). The bio-calcium powder ultrasonicated at 70% amplitude for 15 min had the smallest particle size (3.38 µm) when compared to the control (28.85 µm). When the ultrasonicated bio-calcium was subjected to drying, freeze-drying produced powders with higher calcium solubility but lower whiteness than hot air (tray) drying. The results suggest that the ultrasonication is a potential suitable method to reduce the size of bio-calcium powders, while the drying method slightly affected the product characteristics. The bio-calcium powder could serve as a suitable functional ingredient for food fortification aimed at improving the calcium bioavailability. Particle size of bio-calcium powder from fishbone could affect the mouth feel and calcium solubility when used for food product fortification. This work showed that ultrasonication could be used to obtain up to 10-fold reduction in the particle size of fishbone bio-calcium powders, which promotes increased calcium solubility when subjected to simulated gastrointestinal tract digestion. Few differences in characteristics of the bio-calcium powder were observed for freeze-dried and hot air-dried samples. Thus, an economical, safe, and fast process can be implemented for the production of small particle size bio-calcium powder from fishbone.

Serum and meat antioxidative status of broiler chickens fed diets supplemented with garlic rhizome meal, moringa leaf meal and their composite

Serum and breast meat antioxidative status of broiler chickens fed diets supplemented with moringa leaf meal (MLM), garlic rhizome meal (GRM) and their composite were assessed. Ninety-six-day old Cobb 500 broiler chickens were randomly allotted to four treatment diets: Diet 1 (control), Diet 2 (2.5 g/kg MLM), Diet 3 (2.5 g/kg GRM) and Diet 4 (1.25 g/kg MLM + 1.25 g/kg GRM). Serum superoxide dismutase concentrations were not significantly (P > 0.05) influenced by the diets, whereas there were increased serum catalase concentrations across all the treatment diets with birds on Diet 4 showing significantly (P < 0.05) higher means than those on the control. For the serum glutathione peroxidase, significant (P < 0.05) increases were observed among the broilers on Diets 2 to 4 with those on Diet 2 showing the highest significant difference (P < 0.05) with birds on the control diet. The meat catalase and cholesterol concentrations of the breast meat were not significantly (P > 0.05) influenced by the phytoadditives. However, significant (P < 0.05) decrease in lipid peroxidation was observed across the treatment diets when compared with the control, while the phytoadditives enhanced the breast meat glutathione peroxidase among the broilers on the Diets 2 and 4.

Freeze-dried, oven-dried, and microencapsulation of essential oil from Allium sativum as potential preservative agents of minced meat

The present study was conducted to compare the antibacterial activity of oven-dried and freeze-dried Allium sativum along with its spray-dried microencapsulated essential oil in the preservation of minced beef meat. Allium sativum extracts were tested against mesophilic aerobic microorganisms, coagulase-positive staphylococci, Escherichia coli, Salmonella sp., and the sulfite-reducing anaerobes. A difference between the chemical compositions of powders obtained by the conventional oven-drying and freeze-drying has been verified by HPLC-MS2, freeze-dried fresh garlic powder contains 74% of allicin, and 12% cysteine sulfoxides comparing to the oven-drying garlic powder in which is detected two thiosulfinate isomers: allicin (67%) and allyl-1-propenyl thiosulfinate (21%). CIELAB color analysis was performed to assess the effect of drying temperature on powders. The microflora-inhibiting effect of freeze-dried fresh garlic and the spray-dried microencapsulated essential oil at a concentration of 20% represents a promising way to be used in food systems such as meat and meat products preservation, at 4-8°C.

Effect of Duration and Drying Temperature on Characteristics of Dried Tomato (Lycopersicon esculentum L.) Cochoro Variety

The objective of the present study was to standardise the duration and temperatures of the conventional oven drying methods for best physical and sensory characteristics of dried tomato. The experiment consisted of two factor factorial design (3*2) with three levels of drying temperature (70°C, 80°C and 90°C) and two levels of drying duration (7 and 8 hours) with three replications. An improved and high yielding variety (Cochoro) of tomato released in 2007 for processing and widely grown in Ziwai (Maki), Ethiopia was used. Prior to drying, individual tomato fruits were washed and sliced into uniform thickness (8mm); then, the slices were placed on to the drying trays in a single layer to facilitate uniform drying in hot air oven set at predetermined temperatures per the respective treatments. Data were collected on different physical and sensory attributes and analysed using SAS software (version 9.2). The results showed that titratable acidity, total soluble solids and water absorption capacity were significantly (p≤0.001) increased due to the interaction of degree of temperature and duration of oven drying. In contrast, pH and water activity decreased as the drying temperature and duration increased. Drying at 70°C for 7 hours produced dried tomatoes with the highest sensorial acceptability and physical attributes while higher temperatures (80, 90°C) and longer duration (9 hours) significantly detract the quality of dried tomato. Hence, it is possible to add value and preserve tomatoes through oven drying at the right temperature and optimum duration.