在列表解析中使用str.title来处理每个单词的大写首字母，因为str.capitalize只转换第一个单词的首字母：

df['Column B'] = [[y.title() for y in x] for x in df['Column A']]
df['Column C'] = [[y.capitalize() for y in x] for x in df['Column A']]
print (df)
                                            Column A  \
0  [apple pie, banana milkshake, chocolate ice cr...   
1          [chicken noodles, lamb chops, lime juice]   

                                            Column B  \
0  [Apple Pie, Banana Milkshake, Chocolate Ice Cr...   
1          [Chicken Noodles, Lamb Chops, Lime Juice]   

                                            Column C  
0  [Apple pie, Banana milkshake, Chocolate ice cr...  
1          [Chicken noodles, Lamb chops, Lime juice]

使用pandas.DataFrame.apply

# import required module
import pandas as pd
import numpy as np

# create fake data
df = pd.DataFrame({
    'Column A': [['apple pie', 'banana milkshake', 'chocolate ice cream'], ['chicken noodles', 'lamb chops', 'lime juice']],
})

# create column b, c
df['Column B'] = df['Column A'].apply(lambda x: [y.title() for y in x])
df['Column C'] = df['Column A'].apply(lambda x: [y.capitalize() for y in x])