The effect of Pumpkin peels (Cucurbita maxima) on the quality of Japanese quail flesh

The use and benefit of Pumpkin (Cucurbita maxima) peel is still not prominent and acknowledged by many people till now. The peel which is reported to be abundant with beta-carotene are not palatable and commonly discarded. The main objective of this experiment is to determine the effect of different concentrations of pumpkin peel powder (PPP) as feed formulation on the flesh quality of Japanese quail (Coturnix japonica). The following treatments were applied; commercial feed with 0% PPP (Treatment 1; T1), 2% (Treatment 2; T2); 4% (Treatment 3; T3) and 6% (Treatment 4; T4) for 3 weeks after fully fed with commercial feed for 2 weeks. The main analytical tests conducted were feed analysis, carotenoid content, drip loss, colour and texture. Carotenoid content was analysed by using spectrophotometer. The results obtain indicated that the highest concentration (6%) of pumpkin peel powder showed the highest reading of carotenoid content (p<0.05) while treatment 2 with 2% of PPP obtain the highest weight gain (p<0.05). In conclusion, this study showed that quail feed which supplemented with higher PPP may help in producing quail flesh with antioxidant properties

Effects of different cooking methods and time intervals on physico-chemical and antioxidant properties of Golden pumpkin (Cucurbita maxima)

Effect of different cooking methods with different cooking time on the chemical, physical and antioxidant composition of golden pumpkin (Cucurbitae maxima) was evaluated. Pumpkin flesh has been treated with different cooking methods, which were boiling, steaming and stir-frying at different cooking time (5 and 10 minutes). Chemical analysis showed there was no significant difference (p>0.05) detected for all treatments except for the fat content in stir-fried sample. Colour analysis, which was measured using tristimulus colorimeter showed decreasing of lightness (L*) in all treated samples compared to fresh sample. Total phenolic content was determined using Folin-Ciocalteu method and the antioxidant activity was based on the evaluation of free-radical scavenging activity (DPPH assay). Total carotenoids were measured using spectrophotomer by comparing with β-carotene as the standard. Among treated samples, total phenolic content was found the highest in steamed sample. Heat treatment was found to affect the antioxidant activity in all treated samples, as the percentage of DPPH inhibition was slightly lower than fresh sample. Surprisingly, β-carotene was found to be slightly higher in steamed sample compared to other cooking methods and fresh sample. This study showed that different cooking methods gave some affect to the available antioxidant properties in golden pumpkin

Efficacy of ultraviolet-C irradiation to suppress fruit decay and retain the postharvest quality of dragon fruit (Hylocereus polyrhizus)

Dragon fruit (Hylocereus sp.) is a non-climacteric fruit with a short shelf-life and is easily susceptible to diseases. Chemical pesticides are commonly used to control disease in dragon fruit. However, the efficacy of Ultraviolet-C (UV-C) irradiation at low concentrations as effective germicidal to control fruit decay and prolong the shelf-life on dragon fruit is still unexplored. This study aimed to evaluate the efficacy of UV-C irradiation at lower rates (0, 0.25, 0.5, 0.75, 1.0 kJ m-2) to control the postharvest decay and maintain the quality of dragon fruit. Results revealed that the quality of dragon fruit is dose-dependent. UV-C irradiated dragon fruits at 0.75 and 1.0 kJ m-2 were significantly reduced in fruit body decay, delayed bract yellowing, and prolonged shelf-life. These dosages synergistically slowed down the depletion of total soluble solids and fruit firmness during storage. Also, dragon fruit treated with 1.0 kJ m-2 UV-C exhibited the lowest pH value after the 6th day in storage. UV-C irradiation at this dosage indicated no significant adverse effects in titratable acidity and total water loss. These results indicated that UV-C irradiation at 1.0 kJ m-2 was effective to reduce post-harvest decay and hence prolong the post-harvest quality of dragon fruit storage under ambient conditions

Effect of different concentrations of propolis extract coating on postharvest quality of banana artificially inoculated with Colletotrichum gloesporioides

The coating is one of the methods to prevent postharvest loss in the food industry. Propolis seems to be promising as a coating due to its waxy properties, high antifungal activity and less toxicity. In this study, propolis ethanol extract coating was tested for the antifungal activity against Colletotrichum gloeosporioides, the causative fungus that caused anthracnose disease on bananas (Musa acuminata). All samples were artificially inoculated with C. gloeosporioides and the disease severity index (DSI) was measured. Other postharvest qualities of banana tested were weight loss, total soluble solids (TSS), colour and titratable acidity (TA). Results showed that the control banana was more susceptible to the fungal infection (60% necrosis) compared to the treated banana. The propolis coating successfully inhibited the fungus activity of C. gloeosporioides activity on a banana during storage. The higher concentration of extract coating seems to be better effective against the fungus. Moreover, the control banana showed higher weight loss (6.92%) and total soluble solid (p<0.05) compared to coated banana during storage. In conclusion, bananas treated with an 11% concentration of propolis coating are promising for improving the colour, total soluble solid content and titratable acidity and can inhibit artificially anthracnose disease caused by C. gloeosporioides on a banana

Low heating effects on the total microbial activity and physico-chemical properties of stingless bee (Heterotrigona itama) honey

The high moisture content of stingless bee honey (SBH) is a worrisome problem and heat treatment is used to reduce the moisture and maintain the honey’s quality by destroying the microorganisms that affect the physico-chemical properties of honey during storage. Low heat treatment (45 °C) for 0, 30, 60, 90, and 120 min were conducted to determine the total microbial activity using fluorescein diacetate hydrolysis (FDA). The total microbial population that subsequently affected the physico-chemical properties was also analyzed. The total microbial activities of SBH were significantly reduced after thermal treatment at 45 °C for 90 min (63.76 μg FDA/g/h) and 120 min (62.43 μg FDA/g/h) compared with control (67.127 μg FDA/g/h). Also, the moisture content, electrical conductivity (EC), pH, and free acidity of the low heat-treated SBH at all durations were significantly reduced compared with the control. The total microbial activity was detected as significantly correlated to bacterial and fungal populations, moisture content, EC, pH, and free acidity of low heat-treated SBH. Low heat treatment at 45 °C for 120 min was efficient to reduce the total microbial activity, total acidity, and increasing the pH of SBH. Prolonging the heating duration is suggested to further reduce the water content, total microbial activity and further increase the shelf life of SBH

Stability and esterification of lutein in bread wheat during post harvest storage in comparison with banana.

Lutein is an important micronutrient for humans as well as being the primary contributor to the pale creamy to yellow colour of bread wheat and durum based products but tends to be unstable against heat and UV light. During post harvest storage of bread wheat grain some of the lutein may be converted to mono- and di-fatty acid esters that appear to be more stable forms of lutein. The aims of the work presented in this thesis were: to study the effects of temperature on lutein esterification; to compare the relative stability of free lutein and lutein esters in grain stored under wide temperatures and conditions; to confirm that esterification is an enzymic process; to examine the genetic control mechanisms; to attempt to identify the enzyme and the endogenous substrate source of fatty acids; and finally to compare esterification in wheat grain with the same process in banana fruit tissues. This study utilised a high lutein, ester forming bread wheat, Triticum aestivum L. cv DM5685*B12, a non-ester forming bread wheat cv Haruhikari and a high lutein durum wheat, Triticum durum L cv Kamilaroi, that like many durum cultivars does not form lutein esters. Reverse phase high pressure liquid chromatography (RP-HPLC) was used to quantify the lutein and lutein ester concentrations. Lutein esterification was strongly favoured by low relative humidity (8% RH) and followed a first order reaction rate. The maximum rate of lutein esterification was at ≈80°C, however the optimum temperature for maximum synthesis with minimum degradation was between 50 and 60°C. No ester synthesis was observed at temperature higher than 120ºC. These data were consistent with an enzyme participating in the esterification reaction. Lutein ester was found to be more stable than free lutein with a substantially longer shelf life at a temperature of 60°C. An attempt to establish a bioassay system to study esterification was only partially successful since only very low levels of esterification were achieved in reconstituted samples. Further investigation would be required to optimise the process. The limited data did provide suggestive evidence that free fatty acids were probably not involved, rather the fatty acids were more likely to be derived from phospholipids via an acyltransferase reaction. A hexane-soluble fraction derived from a non-ester forming durum, Kamilaroi, was the only substrate that in the presence of a crude enzyme extract and free lutein gave a significant formation of lutein ester. As esterification appeared to be was enzymatically controlled, the genetic control of ester synthesis was investigated. Lutein esterification was compared in a series of nullisomic-tetrasomic Chinese Spring lines and a Haruhikari (zero ester)//Sunco/Indis.82 (high ester) doubled haploid population. Lutein esterification was controlled by a locus, designated Lute, located on the short arm of chromosome 7D closely linked with the marker loci gwm295, wPt-1163 and wPt-3727. In addition to wheat, esterification in banana, Musa acuminata Colla cv Cavendish group was also investigated. Compared to wheat, different patterns of esterification were observed in banana during the ripening with ester synthesis occurring in both banana peel and flesh during post harvest ripening. Esterification in banana occurred under higher moisture content than in wheat and offers another tissue model for the study of the esterification mechanism. This thesis contributes valuable new information on the formation and genetic control of lutein ester formation in wheat grain and will be of value to manufacturers of wheat products seeking to retain lutein in end-products for delivery to costumers.Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 201

Antifungal properties of water extract propolis coating against anthracnose (Colletotrichum gloeosporioides) on strawberry (Fragaria anannassa)

Anthracnose is a major pre and post-harvest disease. Due to the consumer concerns of the residual effect of the synthetic fungicide, biocontrol from a natural source is highly required by the consumer to reduce the problem. Propolis is a natural antifungal that can be used as a coating to control fruit quality and postharvest losses. This study evaluated the physical and chemical characteristics of strawberry (Fragaria ananassa) induced with Colletotrichum gloeosporioides, coated with water extract propolis (WEP) and stored at 5°C. The effect of coating was evaluated with different concentrations of water extract propolis (WEP) which were control, 10%, 12%, and 14%. The post-harvest parameters such as weight loss, total soluble solids (TSS), anthocyanin, disease severity index (DSI), and firmness were evaluated at two days interval for 12 days of storage. The highest percentage of inhibition (in vitro) was shown by the highest concentration of WEP (14%). Fruits coated with propolis showed reduced deterioration and infection diameter of fungus, as compared to the control (without coating) which already spoiled at day 4. Strawberry coated with 14% concentration of WEP also showed the highest firmness compared to other treatments. Thus, this coating can be used as an alternative method for bio-control of disease to reduce the post-harvest loss of fresh produce

The Effect of Processing Conditions on Production of Resistant Starch Type III (RS3) from Breadfruit Starch

Resistant starchtype III (RS3) possess various beneficial physiological effects as well as functionality in food containing resistant starch (RS). In this study, RS3 is produced from breadfruit (Artocarpus altilis) starch using different processing conditions involving disruption of starch granules, enzymatic debranching of starch polymer, starch retrogradation and drying. Then, the morphology and size of the starch granules were observed using scanning electron microscope (SEM). A sample with the highest RS content (54.59%), denoted as P8 was produced when the breadfruit starch was suspended in distilled water, gelatinised by heating at 90°C for 30 minutes, followed by starch debranching with 20 New Pullulanase Unit Novo (NPUN) enzyme per g starch at 60°C for 24 hours. The suspension was then autoclaved at 121°C for 1 hour and cold stored at 4°C for 24 hours. Further treatment of P8 sample with 0.5 M HCl acid at 60°C for 24 hours, produced HCl-breadfruit RS3 with 57.86% of RS content. It was observed that hydrolysis of breadfruit RS3 sample with HCl produced smoother starch granules with more crystalline region and proportionally increased the RS content when compared to other treated sample. This study revealed that different processing conditions were significantly influenced the percentage of yield and properties of RS type III produced from breadfruit starch

Antifungal activity of extracts against Colletotrichum species in harvested chili

Chili is an important vegetable fruit but is commonly attacked by anthracnose disease during field or storage. A current practical method to control this disease is through synthetic fungicides. Although it shows the effective result, repetitive application of chemical fungicides may build up resistant pathogens, expose the risk to human health, and be regarded as not eco-friendly to the environment. This study aimed to evaluate the antifungal activity of several extracts and their potential to control Colletotrichum sp. in harvested chili. For this purpose, several plant extracts namely garlic, ginger, dragon fruit peel (DFP), and milk were used with the concentration ranged from 5 to 20%. All these extracts and milk were tested through in vitro antifungal assay and in vivo antifungal assay directly on the detached chili. The results show that garlic, ginger, and DFP were able to significantly inhibit the fungal pathogen of Colletotrichum sp. through in vitro study with p<0.05. Based on in vivo study, the only chili treated with 20% garlic extract, 20% ginger extract, and fungicide recorded a significantly lower percentage of disease severity (ds) as compared to the other extracts. Both 20% garlic and 20% ginger extracts showed good potential to inhibit the fungal pathogen. Therefore, the application of natural extracts should be focused and practically used as a control strategy in integrated pest management for plant disease, especially in chili production. This control measure is expected to reduce yield losses, operational cost while mitigating the environmental contamination due to overdose chemical residue

Profiling pH and moisture content of stingless bee honey in closed and opened cerumen honey pots

The aim of this study is to profile the pH and moisture content of stingless bee honey in closed and opened cerumen honey pots from a single hive of stingless bee. The evaluation was conducted in February and September 2020. Portable pH meter and refractometer were used to measure on-field data of honey pH and moisture content. On-field data measurement revealed that the average pH for closed pots was 3.43 while 3.62 for opened pots. Honey measured in September was found to have higher of moisture content with mean value of 32% compared to honey measured in February with 25%. High moisture content is a worrisome problem because it will accelerate quality deterioration of stingless bee honey which mostly contributed by fermentation process. Low pH value also influences the consumer preference as the taste of honey will be more sour. So, this study suggests that wetter season in September could give rise to the moisture content of honey due to higher humidity of surrounding contrarily from dry season in February and could affect the quality of stingless bee honey