Academic literature on the topic 'Kiwifruit juice'

Chitosan (CS) is an effective clarifying agent for fruit juice. However, its low antioxidant ability is a limitation in preserving the antioxidant capacity of the juice during clarification. In this work, an antioxidant CS derivative, tannic acid-modified CS (TA-CS), was used as a clarifying agent to optimise the clarification of kiwifruit juice. By using response surface methodology and the transmittance of the juice as a response, the optimal clarification conditions were obtained as follows: TA-CS concentration of 600 μg mL⁻¹, juice pH of 3.5, and heating temperature of 70 °C. Under the optimal conditions, TA-CS showed an excellent clarification effect on kiwifruit juice, which was confirmed by the high transmittance of 99.3%. Meanwhile, the retention rate of vitamin C in the juice reached 97.0% for the TA-CS treatment, being significantly higher than that for the CS treatment. Our results suggest that TA-CS may be a promising clarifying agent for the production of fruit juice.

Purpose The purpose of this study was to study the effect of kiwifruit juice and tumbling in improving tenderness and to access antioxidant potential of kiwifruit juice. Design/methodology/approach Three treatment groups were made: Spent hen meat was subjected to still marination (SM) and tumbling marination (TM). This meat was used for preparation of whole muscle chicken nuggets and compared with control (without marination) nuggets (Con). These treatments were subjected to analysis of physicochemical characteristics, textural quality, lipid oxidation and sensory quality. Findings SM and TM exhibited higher moisture content and lower protein and fat content than Control SM and TM showed significant (p = 0.132) reduction in firmness from 5.1 to 2.3 and 1.2 Kg/cm2, respectively, and toughness from 14.1 to 6.2 and 3.3 Kg-sec/cm2, respectively, as observed by Warner-Bratzler shear and improvement in texture profile values. Sensory scores for texture, juiciness and overall acceptability were also better for SM and TM. Significant (p = 0.007) reduction was observed in lipid oxidation parameters of SM and TM. Thiobarbituric acid (TBA) values (on 0 day) for SM and TM were 0.18 and 0.15 as compared to 0.28 mg/kg of malonaldehyde for control. Peroxide values (PV) were also lower for SM and TM as 0.44 and 0.33, which were lesser than control (0.62 meq. peroxide/kg). The values for PV, TBA and free fatty acid increased with increase in storage period in all treatment groups. However, the antioxidant activity of kiwifruit juice persisted during whole storage period evidenced by lower values of lipid oxidation parameters for SM and TM than Control at each storage interval. Research limitations/implications Further research may be carried out to compare the tenderizing potential of kiwifruit juice with other plant proteases and physical tenderizing techniques. Spent hen meat utilization can be done with greater efficiency by using such techniques in meat caterings. Practical implications Spent hen meat utilization can done with greater efficiency by using such techniques in meat caterings. Originality/value Marination with kiwifruit juice improved the quality characteristics of chicken nuggets made from spent hen meat without altering its sensory quality. Tumbling was found to be beneficial in enhancing the tenderizing effect. Therefore, marination with kiwifruit juice can be used as a processing technology to use spent hen meat in preparing value added products.

Kiwifruit is an interesting alternative to chymosin for milk coagulation. Although the clotting properties of actinidin (the proteolytic agent present in kiwi) have been widely investigated, little is known about the nutraceutical and organoleptic effects of kiwifruit on the characteristics of cheese. We investigated kiwifruit pulp, compared to calf rennet, in cheesemaking using sheep and buffalo milk. Although the kiwifruit extract showed a longer coagulation and syneresis time than calf rennet, it could nevertheless be exploited as a plant coagulant due to its positive effect on the nutraceutical properties. In fact, the sheep and buffalo cheese were higher in polyphenols and phytosterols than the cheese obtained using calf rennet. In addition, the nutraceutical properties were enhanced, with just a slight effect on the aroma of the cheese.

Tenderness, juiciness, colour and flavour are the most important meat quality attributes affecting the consumer acceptance. Maintaining the consistency of meat products by avoiding variable quality has become a major concern and great challenge to the meat industry. This in turn will also benefit meat end-users in the marketplace by having more tender meat. The present study was designed to evaluate the overall effects of pre-rigor infusion with kiwifruit juice, which contains the plant protease, actinidin, on lamb quality. A total of 18 lambs (12 months old) were divided into three treatment groups (6 lambs per each treatment). After exsanguination, lamb carcasses were infused (10% body weight) with fresh kiwifruit juice (Ac), water (W) and compared with a noninfusion treatment which acted as a control (C). Samples from different muscle/cuts (longissimus dorsi (LD) vs leg chops) at different post-mortem times (1 day post-mortem vs. 3 wks vacuum packaged storage at 2°C) and display time (0 to 6 days after the post-mortem storage) were analysed to monitor the changes on meat physical properties (e.g., tenderness, temperature, drip and cooking loss, colour), biochemical changes (pH, proteins and lipids) and volatile flavour compounds after the infusion treatments. The most tender meat (lowest shear force values) (P < 0.001) detected in the Ac carcasses post-mortem compared with C and W carcasses demonstrated that kiwifruit juice was a very powerful meat tenderizer, and could contribute to the meat tenderization process efficiently and effectively. Compared with C and W carcasses, the enhanced proteolytic activity (P = 0.002) resulting from the actinidin in kiwifruit juice in Ac carcasses caused degradation of the myofibrillar proteins and the appearance of new peptides during postmortem ageing. A slight positive effect in a*-value (redness) and decreased lipid oxidation, found in leg chops, was thought to be caused by the natural antioxidants in kiwifruit juice. Kiwifruit juice infused into the meat did not alter (P > 0.05) the volatile flavour compound profile indicating that the meat from Ac treated carcasses maintained its natural lamb flavour. No treatment differences were found for the temperature decline (P > 0.05) between the infused treatments and C. The higher rate of pH decline (P < 0.05) found in W carcasses might have contributed to the higher drip and cooking loss. The unbound water in meat might contribute to the higher L*-values (lightness) found in W carcasses. In summary, the proteolytic tenderizing infusion treatment using kiwifruit juice is a feasible approach for the commercial meat industry to increase profits, and also could satisfy the eating quality standards required by the consumers. In addition, tenderizing meat by using kiwifruit juice could also provide the kiwifruit processors an additional option for use of their product to gain a more profitable return.