机械脱皮白胡椒的品质评价及风味分析

为探究胡椒脱皮机不同脱皮条件对白胡椒白度值、黑果率、碎果率、胡椒碱含量、胡椒精油含量等理化指标的影响,通过调节熟化频率（熟化频率分别为10、15、20、25、30 Hz）和脱皮频率（脱皮频率分别为25、30、35、40 Hz）分别获得5组、4组白胡椒。分析了胡椒碱含量、胡椒精油的成分及含量,以白胡椒的气味、颗粒及组织状态、颜色、喜好度作为感官评价指标,采用AHP层次分析法确定评价指标权重,以模糊数学感官评价法和隶属函数值法进一步评价白胡椒品质。结果表明：熟化频率为20 Hz,脱皮频率为35 Hz时,白胡椒感官评价得分最高,为88.00分;隶属函数值计算结果表明熟化频率为20 Hz,脱皮频率为35 Hz的白胡椒平均隶属函数值差值最大,为2.71,品质最好。不同机械脱皮条件下生产的白胡椒精油共鉴定出42种化合物,含量较高的共有化合物为3-蒈烯、β-石竹烯、柠檬烯等。实验结果为胡椒品质评价及工艺优化提供参考,对胡椒工业化生产具有良好的指导意义。     

不同加工方法对白胡椒品质的影响

为确定白胡椒的加工工艺,比较传统水泡法、流水浸泡法、机械脱皮法、酶辅助机械脱皮法对白胡椒水分含量、总灰分、挥发油、胡椒碱、不挥发性乙醚提取物、碎果率、黑果率、破损率、白度值、气味特性的影响。结果表明,4种方法加工的白胡椒水分、总灰分、挥发油、胡椒碱、不挥发性乙醚提取物含量、碎果率差异不显著;传统水泡法加工的白胡椒白度值最高;酶辅助机械脱皮法加工的白胡椒黑果率最低,香味最浓郁。酶法辅助机械脱皮法加工的白胡椒水分含量、总灰分、挥发油、胡椒碱、不挥发性乙醚提取物、碎果率、黑果率、白度值、破损率依次为13.14%±0.21%、1.31%±0.080%、(2.31±0.16)mL/100g、5.42%±0.17%、7.08%±0.15%、1.76%±0.12%、2.35%±0.15%、75.35±2.18、3.68%±0.23%。综合来看,酶辅助机械脱皮法加工的白胡椒品质最优,白胡椒的加工宜采用酶辅助机械脱皮法。     

胡椒的酶辅助机械脱皮工艺优化及品质分析

在机械脱除胡椒果梗、果粒和蒸汽熟化基础上,优化胡椒的酶法脱皮工艺,并测定其品质特性。以脱皮率、白度值为评价指标,采用果胶酶脱除胡椒果皮,在单因数实验基础上,通过正交实验优化脱皮工艺,测定白胡椒中水分含量、总灰分、不挥发性乙醚提取物、挥发油、胡椒碱、碎果率、黑果率、白度等理化性质。结果表明,果胶酶脱除胡椒果皮工艺条件为:温度50℃、pH4、底物质量浓度2.0 kg/L,酶添加量150 U/g、酶解时间30 min,此方法制得的白胡椒中水分含量、总灰分、不挥发性乙醚提取物、挥发油、胡椒碱、碎果率、黑果率、白度值、脱皮率依次为(13.14±0.23)%、(1.31±0.08)%、(7.08±0.15)%、(2.31±0.16)mL/100 g、(5.42±0.17)%、(1.76±0.12)%、(2.35±0.15)%、75.35±2.18、(97.35±1.37)%。研究表明,酶辅助机械脱皮法脱除胡椒果皮可行。     

不同处理方式对胡椒精油组成及含量的影响

为研究不同处理方式对胡椒精油成分及含量的影响,采取杀青,杀青后存放1~2 d,红皮胡椒杀青及未杀青的方式制备黑胡椒,分别杀青处理5,10 min,蒸制5 min后脱皮制备白胡椒。使用气-质联用仪(GC-MS)分析黑胡椒与白胡椒精油组成成分及相对含量。结果表明:(1)石竹烯、δ-榄香烯、D-柠檬烯、胡椒烯、3-蒈烯、α-石竹烯和β-蒎烯为胡椒精油中含量较多的化学成分。(2)不同处理方式对胡椒精油化学成分的种类与含量有一定影响,黑胡椒与白胡椒精油化学成分的种类及含量差异显著。     

4 种胡椒精油风味特征分析

研究以黑胡椒、白胡椒、青胡椒和胡椒鲜果为原料提取的精油及精油风味特征。采用水蒸气蒸馏法提取精油,比较不同胡椒的精油提取得率,通过气相色谱-质谱法、电子鼻及定量描述性感官分析,对不同胡椒精油风味特征进行分析。结果表明,黑胡椒、白胡椒、青胡椒和胡椒鲜果的精油提取得率分别为1.718、1.867、1.487 mL/100 g和3.229 mL/100 g,胡椒鲜果的精油提取得率显著高于白胡椒、黑胡椒和青胡椒。从4 种胡椒精油中共鉴定出48 种物质,主要成分均为β-石竹烯、3-蒈烯、D-柠檬烯、β-蒎烯、δ-榄香烯、β-月桂烯。电子鼻数据证实,判别因子分析比主成分分析更易区分不同胡椒精油。感官评价显示胡椒鲜果精油的胡椒香比其他3 种精油明显,接受程度更高。偏最小二乘回归分析结果表明,芳香、草本、胡椒香属性与(＋)-α-蒎烯成分呈正相关。实验结果为胡椒精油产品开发及升级提供参考。     

响应面试验优化胡椒鲜果油炸工艺

为优化胡椒鲜果油炸的工艺,选取油炸温度、油炸时间、料油比为影响因素,以油炸胡椒鲜果中胡椒碱和胡椒精油含量为指标进行研究。在单因素试验的基础上,采用Box-Behnken试验设计构建多项式回归方程的模型,通过响应面分析得到胡椒鲜果最优油炸工艺为：油炸温度92 ℃、油炸时间3 min、料油比1∶1。此条件下胡椒鲜果油炸品质最优,胡椒碱含量预测值为4.28 g/100 g,胡椒精油含量预测值为1.73 mL/100 g,而胡椒碱含量真实值为4.23 g/100 g,胡椒精油含量真实值为1.71 mL/100 g,与预测结果相对偏差仅为1.27%和1.24%。     

四种方式制备的黑胡椒风味成分分析

本文分别对四种加工方式(直接日晒、热烫处理后日晒、日晒1 d轻度发酵、日晒2 d轻度发酵)过程中的黑胡椒风味成分进行分析。采用水蒸气蒸馏法提取胡椒精油,四种产品中胡椒精油的含量分别为1.10、1.09、1.16、0.89 m L/100 g,发现四种加工过程中胡椒精油均有较大程度的损失,损失率范围63%~71%。经GC-MS检测四种加工方式所得产品中的精油分别鉴定出19、17、23、22种化合物,其总检出量在95%以上;其中α-蒎烯、β-蒎烯、3-蒈烯、D-柠檬烯、蛇麻烯、反式-石竹烯、β-甜没药烯在四种产品中的含量较高,最高的为反式-石竹烯,相对含量范围43.47%~56.16%。利用HPLC法检测胡椒碱含量,四种加工产品中胡椒碱含量分别为3.64、3.53、3.32、3.58 g/100 g,胡椒碱在加工过程中的损失率范围为9%~17%。     

胡椒幼果与黑、白胡椒香气成分的比较研究

为比较胡椒幼果与黑、白胡椒香气成分的差异,按照L9(34)正交实验设计,通过超声波处理提取胡椒幼果、黑胡椒和白胡椒的胡椒油树脂,再采用GC-MS测定比较其香气成分。结果表明:胡椒幼果油树脂中分离出25种物质,鉴定出20种;黑、白胡椒油树脂中均分离出28种物质,鉴定出23种;胡椒油树脂香味成分主要是α-蒎烯、β-蒎烯、3-蒈烯、D-柠檬油精、4-乙烯基-4-甲基-3-(1-甲基乙烯基)环己烯、石竹烯和胡椒碱等;胡椒幼果具有比黑、白胡椒更为清新、丰满的香气,油树脂得率最高,且其香气成分的相对含量只是略低于黑胡椒和白胡椒,因此可用胡椒幼果油树脂代替黑、白胡椒油树脂开发新型胡椒类产品。     

鲜胡椒酶法快速脱皮工艺比较

选用摇床振摇、带刷搅拌和波轮搅拌三种脱皮方式,结合生物酶法快速脱除鲜胡椒果皮,通过测定脱皮率和白胡椒色差L值,单因素试验优化生物酶法脱皮条件,比较不同脱皮方式对新鲜胡椒的脱皮效果,对酶液进行重复利用,最大限度降低酶液成本,并对不同脱皮方式得到的白胡椒的品质进行了比较。结果表明:三种搅拌方式中,波轮搅拌对胡椒生物酶法脱皮效果最好。使用波轮搅拌方式,新鲜胡椒烫漂5min,复合酶液浓度为1.25%,脱皮温度为45℃,使用波轮搅拌方式搅拌3h,脱皮率为98.6%,色泽好。根据酶液重复利用效果进行分析,表明重复4次最经济。对不同脱皮方式得到的白胡椒进行比较,表明波轮搅拌和带刷搅拌更有利于保持白胡椒的色香味、品质。     

胡椒果皮高效脱胶菌的筛选、鉴定及初步应用

为实现胡椒生物酶法高效脱皮,从海南胡椒种植园的土样中采集样品,以茵株产果胶酶活力的大小和胡椒脱皮效果为筛选指标,分离、筛选出1株胡椒果皮高效脱胶茵WC 0021;对其进行生理生化及16SrDNA序列分析,初步鉴定为蜡状芽孢杆菌(Bacillus cereus).将菌株WC0021发酵生产的果胶酶用于胡椒鲜果脱皮试验,结果表明,在pH为7.5,温度为35℃的条件下,所产果胶酶2天内可将胡椒果皮脱除干净,所得白胡椒中挥发油和胡椒碱的含量分别是3.37 mL/100 g和4.25 g/100 g,菌落总数为1.0×103 cfu/g,感官评价为优.     

Effect of Steam Temperature, Speed of Cooling and Cutin Disruption in Steam and Lye Peeling of Apples

A laboratory model steam peeler was adapted to accept superheated steam and direct injection of cold water in order to study the effect of rapid heating with superheated steam and rapid cooling under partial vacuum on the peeling efficiency of‘Red Delicious’apples. A test was also designed to determine the effect of physical disruption of the cutin layer on the efficiency of caustic peeling. Steam peeling resulted in higher peeled yields and brighter product color than caustic peeling. The peeled yields were 97.5% for superheated steam-peeled apples with flash cooling, 91.7% for caustic peeled fruit which had a prepeel treatment to physically disrupt the cutin layer, 85.8% for conventionally caustic-peeled fruit, and 82.7% for the mechanically peeled control.     

货架陈列期间光照处理对鲜切青椒品质的影响

为研究白光、红光、蓝光、绿光光照以及避光处理对鲜切青椒（Capsicum annuum L.）品质的影响,将鲜切青椒在货架陈列期用不同光照处理,贮藏5 d后,比较鲜切青椒质量损失率、颜色、相对电导率、丙二醛含量和风味的差异。结果发现：在各光照处理组中,绿光处理组鲜切青椒的质量损失率最低,为3.75%,且该处理对可溶性固形物质量分数、果实水渍化损伤程度、果实颜色变化的影响均较小,与新鲜样品相比,其色差仅为3.22,显著低于白光处理组（P＜0.05）;并且与白光处理组相比,绿光处理对鲜切青椒的风味没有显著影响（P＞0.05）。因此,绿光处理有助于维持鲜切青椒在货架陈列期的品质。     

FREEZE PEELING IMPROVES QUALITY OF TOMATOES

SUMMARY— A process of peeling tomatoes using low temperature-short time freezing was perfected. Liquid nitrogen (BP-196°C was used as the refrigerant for freezing the skin and only a thin layer of cells just beneath the skin. The fruit was immediately thawed, after which the skin was quickly and easily removed from the fruit. Liquid nitrogen-peeled samples were evaluated for loss of peel and trim, as well as lycopene and carotene in the peeling process and these losses compared with samples peeled in boiling water. The losses in peel and trim were reduced by approximately 50%, and significantly less lycopene was lost by nitrogen peeling. The peel and trim of fall tomatoes had a greater amount of lycopene and carotene than spring tomatoes. The nitrogen-peeled samples were canned without additives, with sodium chloride and with calcium chloride added and compared with samples peeled with boiling water. There was a decrease in the percentage of broken fruit in the canned tomatoes peeled by liquid nitrogen. Titratable acidity and °Brix were higher and pH was lower in these samples. Color of the homogenized canned product was not statistically different; however, the nitrogen-peeled tomatoes had a better visual color. The calcium chloride added-nitrogen-peeled samples possessed a higher degree of firmness than the comparably treated boiling-water-peeled samples, indicating that the nitrogen-peeled tomatoes utilized the added calcium to a greater extent in firming.     

水蒸气蒸馏与顶空进样GC-MS分析白胡椒挥发性成分

分别采用水蒸气蒸馏法和顶空加热提取白胡椒挥发性成分,并对其进行气相色谱- 质谱(GC-MS)分析,发现不同采集方法制备的白胡椒挥发性成分有所不同。采用顶空进样技术,可鉴定出白胡椒中32 个挥发性化学成分;采用水蒸气蒸馏法可鉴定出26 个挥发性化学成分;两种采样方法进行的GC-MS 分析,有18 种相同化合物,但相对含量有一定差异。两种样品采集方法,分别提供了白胡椒中不同沸点的挥发物的化学信息,从而建立更全面的白胡椒挥发性成分GC-MS 表征体系。     

三种胡椒脱皮方式污水水质指标比较分析

以海南文昌胡椒鲜果为原料,对传统水沤法(A)、微生物酶法(B)和冷冻机械脱皮法(C)等三种不同的脱皮方法产生的污水中6个水质综合性指标(COD,BOD_5,pH,氨氮,TN和TP)进行了测定和比较,并对所得白胡椒品质进行对比分析。结果显示:三种脱皮方式所产污水水质指标差异很大,COD值为742.31±23.82～1.89×10~4±332.90 mg/L,BOD_5值为445.54±23.68～9.21×10~3±130.13mg/L,pH为5.03±0.05～7.44±0.06,氨氮值为59.88±4.56～164.47±8.85mg/L,TN为101.23±18.73～499.02±27.59mg/L,TP为17.78±0.44～41.92±2.95mg/L,均为劣V类水;污水的污染程度依次是A样污水B样污水C样污水;三种不同的脱皮方法污水BOD_5/COD均大于0.4,BOD_5/TN均大于4.00,BOD_5/TP均大于25,表明胡椒脱皮污水可生化性较好,脱皮污水反硝化作用中碳源含量充足,污水水质满足生物除磷需求。污水处理技术可考虑多种生化处理技术合理组合。微生物酶法脱皮所得白胡椒品质最优,而冷冻机械法脱皮时间最短。为实现胡椒提质增效和产业化发展,传统的水沤法脱皮必须加速淘汰,寻求机械脱皮法和微生物酶法相结合的新型加工方法。     

高剂量辐照胡椒粉对胡椒碱影响研究

研究发现高剂量辐照胡分时胡椒碱在水和乙醇抽提溶液中是不稳定的，而胡椒粉中的胡椒碱在大于１０ＫＧＹ的辐射下处于稳定状态，高剂量辐照处理黑白胡椒娄，胡椒碱含量无显著性意义变化。     

PEELING AND THE PHYSICAL AND CHEMICAL PROPERTIES OF KIWI FRUIT

Hand peeling of kiwi fruit has some disadvantages such as difficulty during peeling, increase of loss in weight and nutritional value. Peeling of kiwi fruits with alkali (NaOH) was investigated. Some chemical (acidity, pectin, and chlorophyll) and physical properties (Hunter color value and weight loss) of the fruits were determined after selected alkali peeling methods were used. Peeling methods at 80, 90 or 100C temperatures; in 13, 18 or 23% of NaOH solutions and for 3, 4 or 5 min durations were tested and compared with hand peeling. Weight (fruit tissue) loss in hand peeling was higher than alkali peeling. Peeling with alkali was easier. Nutritional value (ascorbic acid content) of alkali peeled fruits was higher than hand peeled kiwi fruit. Because of less weight loss, better green color and high pectin content the method including 15% of NaOH solution at 95C for 4 min was selected as most advantageous peeling method.     

Studies on the chemical and flavor qualities of white pepper (Piper nigrum L.) derived from five new genotypes

Here, we examine the chemical quality (total protein, total lipid, starch, piperine, and essential oil) and flavor quality of white pepper (Piper nigrum L.) derived from five new genotypes (Jianyin-1, Banyin-1, Banyin-2, Banyin-3, and Banyin-4). We employed headspace solid-phase micro-extraction gas chromatography mass spectrometry (HS-SPME-GC-MS) to analyze major volatiles, electronic nose (E-nose) to analyze volatiles of unknown nature, and sensory testing to assess flavor quality of white pepper derived from these five genotypes. The piperine and essential oil values were significantly higher in Jianyin-1 than in any of the other samples, and this was in accordance with the sensory evaluation results, which indicated that this sample also possesses the most intense pungency notes of all of the samples. The characterization of the chemical quality, volatile compounds, and volatile profiles of all five pepper cultivars showed a clear difference between Jianyin-1 and all of the other samples, perhaps indicative of its unique hybrid origin for the four latter genotypes. The E-nose pattern matching used to examine the volatiles of unknown nature of white pepper derived from all five genotypes further supported our sensory and instrumental data and suggested that Jianyin-1 is a promising and pungent pepper cultivar useful for cultivation for human consumption.     

Assessment of the N-nitrosopiperidine formation risk from piperine and piperidine contained in spices used as meat product additives

The N-nitrosopiperidine (NPIP) formation in blends of spices and nitrite curing salt was investigated in relation with the piperine and piperidine contents in spices. Firstly, two analytical methods were developed. Piperine was extracted with dichloromethane by means of accelerated solvent extraction (ASE) and determined by high-performance liquid chromatography (HPLC)–diode array detector (λ = 343 nm). A selective hydroextraction of piperidine using ASE and its quantification by HPLC–ELSD was applied. Both methods were sufficiently sensitive and accurate (limit of detection, limit of quantification, and recovery: 0.28, 0.84 μg, and 98.9 ± 2.6 % for piperine, and 5.76, 17.45 μg, and 95.9 ± 2.9 % for piperidine, respectively). Secondly, both compounds were quantified in commercial samples (black and white pepper, paprika, chili pepper, allspice, and nutmeg). The maximum amount of piperine (21.12 mg g^?1) was found in pepper, while the other spices contained only traces. Piperidine was detected mainly in the pepper samples, whereby the highest concentration was found in the white pepper extract (11.42 mg g^?1). Thirdly, during the storage of spices blended with nitrite curing salt, the NPIP content was determined, using a gas chromatograph coupled with a thermal energy analyzer. Against our expectations, no NPIP formation was observed in the curing mixture which contained white pepper extract. This result remains in contrast with the white pepper mixture, in which the NPIP content significantly increased from not detected to 9.80 ± 0.41 ng g^?1 after the 2 months storage period. In conclusion, high amounts of piperine or piperidine in spices do not systematically result in the formation of NPIP, when blended with nitrite curing salt .